The plaintiff, T.F., and the defendant, B.L., are two women who lived together from 1996 to 2000. During this time, the plaintiff became pregnant through artificial insemination, and in July, 2000, after the couple had separated, she gave *523birth to a child. In January, 2001, the plaintiff filed a complaint in the Probate and Family Court Department. Based on theories of promissory estoppel and breach of an oral contract,1 she requested that the defendant be ordered to pay child support under the child support guidelines. See G. L. c. 119, § 28 (d). The judge found that there was an agreement “to create a child,” which the defendant had breached. However, the judge did not issue an order of support. Instead, she reported the matter to the Appeals Court pursuant to G. L. c. 215, § 13, see Gray v. Commissioner of Revenue, 422 Mass. 666, 667 (1996), for a determination whether “parenthood by contract is the law of Massachusetts.” If this question were answered in the affirmative, she opined, “then [the defendant] is a parent.” We granted the plaintiff’s application for direct appellate review. We conclude that while the plaintiff has established the existence of an implied agreement, “parenthood by contract” is not the law of Massachusetts and the agreement is unenforceable as against public policy. Therefore, this defendant has no obligation of child support and the Probate and Family Court cannot create such an obligation pursuant to its equity jurisdiction.
Background. We summarize the facts found by the Probate and Family Court judge, which findings were warranted by the evidence. The plaintiff and defendant met in 1995, and began living together in the fall of 1996. On May 30, 1999, the couple held a “commitment ceremony.” Subsequently, they pooled their money and nominated each other as beneficiaries of their respective life insurance policies and retirement plans. The plaintiff had long wanted to have a child, and communicated her feelings to the defendant on several occasions. The first such conversation occurred as early as six months into the relationship. The defendant, who had grown up in an abusive household, doubted her own fitness to be a parent. She also had experienced psychological problems in the past, and was undergoing treatment for a recurrence of depression in the spring *524and summer of 1999. The defendant continued her resistance to having a child until one day in June or July of 1999, when she telephoned the plaintiff at work and told her that she had changed her mind. The plaintiff suggested they talk more about it that evening.
The couple did discuss the matter further (the 1999 conversation). They covered such topics as whether they would rather have a boy or a girl, the defendant’s reasons for her change of heart, whether the defendant’s brother would be a suitable sperm donor, baptism and schooling, and the division of labor between the couple, should they have a child. As a result of the 1999 conversation, the plaintiff scheduled an appointment with her doctor to discuss pregnancy. The plaintiff went to that appointment alone, but subsequently both parties attended appointments with a second doctor at a facility specializing in reproduction and fertility procedures (clinic). This doctor performed tests that disclosed that the plaintiff had a condition that would make pregnancy difficult and would require delivery by Caesarian section. The parties discussed whether the defendant could be the birth mother instead, but a degenerative disc in her back would have made pregnancy even more difficult for her. After rejecting other options such as adoption or a foster child, the parties decided to proceed with the plaintiff’s artificial insemination.
On August 6, 1999, the clinic presented the couple with a document entitled “Consent Form: Therapeutic Donor Sperm Insemination.”2 The parties worked together to select an anonymous donor. The couple used joint funds for insemination and prenatal care expenses. The defendant’s actions during this period were at least in part an effort to preserve her relationship with the plaintiff, which she believed would have suffered had she attempted to prevent the plaintiff from having a child. The defendant told her sister and a friend that, from the time of the 1999 conversation, she “went along” with having a baby because she got “tired of the arguments” and “didn’t want to take [the plaintiff’s] dream away.”
*525After one unsuccessful insemination, the parties discussed how many more such procedures they could afford, and agreed to go forward with a further attempt. In December, 1999, the plaintiff became pregnant as the result of the second insemination.
The parties’ relationship deteriorated in the following months, and the defendant moved out of their apartment in May, 2000. Prior to leaving, the defendant expressed her regrets about being a “separated parent,” said she desired to adopt the child, and “promised financial support and promised to talk later about the details since she wanted to just focus on the break-up of the relationship at that time.” On July 1, 2000, the plaintiff went into premature labor and gave birth to a boy.
We recite the facts following the conception and birth of the child as they may be relevant to the parties’ contractual intent. See Martino v. First Nat’l Bank, 361 Mass. 325, 332 (1972), quoting Pittsfield & N. Adams R.R. v. Boston & Albany R.R., 260 Mass. 390, 398 (1927) (“There is no surer way to find out what parties meant, than to see what they have done”). The defendant visited the mother and child in the hospital several times, participated in selecting his name, and promised to provide support and to change her work hours to help raise him. During one of these visits, the defendant gave the plaintiff $800. On July 26, 2000, the defendant sent pictures of herself with the child, via the Internet, to friends accompanied by the message: “I hope you all enjoy the pics of my wonderful, beautiful boy.” In October, 2000, the parties argued for over an hour about support for the child, who, as the result of his premature birth, required a great deal of medical attention. The plaintiff had been parenting the child and working full time, and wanted financial assistance from the defendant. The defendant “acknowledged that she was not paying child support because she was angry at [the plaintiff].” Later that month, the defendant sent a letter to the plaintiff, declaring that she desired no further contact with the plaintiff or the child.
The judge found that there was no written agreement between the parties regarding having a child together, that the defendant is not biologically related to the child, and that she has never lived with him. The judge found further that the defendant’s *526name does not appear on the birth certificate, that she did not adopt the child, and that she has made no financial contributions for the benefit of the child, except the payment of $800 to the plaintiff shortly after the baby was bom.
Analyzing the facts, the judge concluded that there was no evidence of an explicit oral promise by the defendant, except to “explore the possibility of having a child.” However, the judge concluded that this promise, because of the defendant’s subsequent behavior and failure to “stop or slow down” the plaintiff’s pregnancy, “grew naturally and actively into the creation of a child,” and thus the creation of a binding contract between the parties. The defendant breached this contract, the judge continued, by refusing to perform the obligations of parenthood (i.e., to provide child support).
Analysis. The plaintiff’s argument for imposing a child support obligation on the defendant is essentially two pronged. First, she claims that the defendant entered into an enforceable implied contract with her to coparent a child, or at least that she impliedly promised to support the child, and is now estopped from denying that support. The defendant’s refusal to pay child support, the argument goes, is therefore a breach of contract. Second, the plaintiff asserts that an order of child support in the present situation would be consistent with oft-expressed legislative policies as manifested in related statutes, and that the “broad and flexible” equity powers of the Probate and Family Court can and should be invoked to implement said polices. We discuss these arguments in turn.
a. “Parenthood by contract.” The plaintiff does not contend that there was any express written agreement between the parties,3 but rather that the defendant’s initial statement, in the summer of 1999, that she wished to discuss having a child, followed by her course of conduct, reflect an implied contract to create a child. In the absence of an express agreement, an implied contract may be inferred from (1) the conduct of the *527parties and (2) the relationship of the parties. See W.A. Snow Iron Works, Inc. v. Chadwick, 227 Mass. 382, 390 (1917); LiDonni, Inc. v. Hart, 355 Mass. 580, 583 (1969). See also Grant v. Carlisle, 328 Mass. 25, 29 (1951). An implied contract requires proof that there was a benefit to the defendant, that the plaintiff expected the defendant to pay for that benefit, and that the defendant expected, or a reasonable person should have expected, that he or she would have to pay for that benefit.4 LiDonni, Inc. v. Hart, supra at 583. When the defendant was, or should have been, aware of the plaintiff’s expectations in this regard, the defendant’s failure to object can create a contract. E.g., Therrien v. Leblanc, 282 Mass. 328, 331 (1933); Maynard v. Fabyan, 267 Mass. 312, 315 (1929). The defendant’s subjective intent is irrelevant when she knows or has reason to know that her objective actions manifest the existence of an agreement. See Restatement (Second) of Contracts § 19 (1981).
In this case, the evidence warranted the judge’s finding that there was an agreement by the defendant to undertake the responsibilities of a parent in consideration of the plaintiff’s conceiving and bearing a child. Although the defendant claims that the plaintiff should not have relied on her passive silence, the judge reasonably concluded that the circumstances and relations of the parties, as stated in her findings, told a different story. The parties cohabited for several years as a couple, pooling all their financial resources. After the 1999 conversation, the plaintiff agreed to conceive and give birth to a child. Following this agreement, the defendant not only did not object, but actively participated in medical decisions and procedures, and in discussions about the child’s future and the finances related to the conception and raising of the child. Furthermore, the judge found that the defendant intentionally manifested an outward desire to have a child in order to maintain her relationship with the plaintiff. A finding of an implied contract based on these facts, while not compelled, was certainly permissible.5
The conclusion does not end our analysis; the question *528remains whether the court can enforce this contract. Contracts between unmarried cohabitants regarding property, finance, and other matters are normally enforceable. See Wilcox v. Trautz, 427 Mass. 326, 332 (1998). Such contracts may concern the welfare and support of children, provided they do not contravene the best interests of the child. Id. at 334 n.7. See E.N.O. v. L.M.M., 429 Mass. 824, 831, cert. denied, 528 U.S. 1005 (1999).6 Contracts between unmarried same-sex couples concerning the welfare and support of a child stand on the same footing as any other agreement between unmarried cohabitants. See id. at 831 n.9. However, when a contract violates or conflicts with public policy, we treat it as void and will not enforce it. A.Z. v. B.Z., 431 Mass. 150, 160 (2000), and cases cited. Beacon Hill Civic Ass’n v. Ristorante Toscano, Inc., 422 Mass. 318, 320-321 (1996). Parsons v. Trask, 7 Gray 473, 476-477 (1856). Contrast Green v. Richmond, 369 Mass. 47, 49-52 (1975). This is such a contract.
In A.Z. v. B.Z., supra at 159-160, we refused to enforce an agreement that compelled a party “to become a parent against his or her will.” In that case, the plaintiff successfully prevented his estranged wife from using his own sperm (which had been frozen and stored by an in vitro fertilization clinic) to create a child. Id. at 150-153. “[Fjorced procreation,” we concluded, “is not an area amenable to judicial enforcement.” Id. at 160. The present case is factually distinguishable in that the defendant’s contribution to the conception and birth of the child arose from contractual intent rather than from her genetic material. *529However, important concerns underlying that decision also apply here.
We determine public policy by looking “to the expressions of the Legislature and to those of this court.” Id. at 160-161, citing Capazzoli v. Holzwasser, 397 Mass. 158, 160 (1986). In the A.Z. case we noted that, by statute, a contract to enter into a marital relationship is not enforceable. Id. at 161, citing G. L. c. 207, § 47A. We also discussed earlier cases that had “indicated a reluctance to enforce prior agreements that bind individuals to future family relationships.” Id., citing R.R. v. M.H., 426 Mass. 501, 510 (1998) (agreement by which surrogate mother agreed to give up child at birth was unenforceable unless agreement contained, inter alla, “reasonable” waiting period consistent with waiting period in adoption surrender); Capazzoli v. Holzwasser, supra at 160-161 (contract requiring individual to abandon marriage unenforceable). See A.R. v. C.R., 411 Mass. 570, 574-575 (1992) (where plaintiff was not biological father of two children, he could not be equitably estopped from denying paternity based on representations he made to their mother).7 We concluded that in order to protect the “freedom of personal choice in matters of marriage and family life,” A.Z. v. B.Z., supra at 162, quoting Moore v. East Cleveland, 431 U.S. 494, 499 (1977), “prior agreements to enter into familial relationships (marriage or parenthood) should not be enforced against individuals who subsequently reconsider their decisions.” A.Z. v. B.Z., supra.
The principles expressed by this court in A.Z. v. B.Z., supra, are applicable, and of like force, in the present case. The decision to become, or not to become, a parent is a personal right of *530“such delicate and intimate character that direct enforcement ... by any process of the court should never be attempted.” Id., quoting Kenyon v. Chicopee, 320 Mass. 528, 534 (1946). “Parenthood by contract” is not the law in Massachusetts, and to the extent the plaintiff and the defendant entered into an agreement, express or implied, to coparent a child, that agreement is unenforceable.8’9
The dissent acknowledges that the agreement to create a child was unenforceable, but insists that this agreement “includes” an enforceable promise to pay child support. Post at 535. Our authority to enforce the lawful portion of an otherwise illegal contract depends on whether that portion is severable from the larger agreement. Bishop v. Palmer, 146 Mass. 469, 474 (1888) (“If the bad part of the consideration is not sever-able from the good, the whole promise fails”). In the present case, the appropriate inquiry is whether there was a specific identifiable agreement to support the child contained within the implied contract to create and parent the child, and, if so, whether that agreement is severable from the implied contract. The Probate and Family Court judge suggested that an agreement to become a parent inherently involves four promises: (1) that the “parties will continue to love the child,” (2) “support each other,” (3) “provide child care,” and (4) “provide financial support for the child.” Nothing in the record gives substance or meaning to any specific promise to provide child support separate and apart from the implied agreement to create a child; support was, as the judge stated, one of the inherent consequences of parenthood. Furthermore, where a portion of a contract is separably enforceable, that portion would ordinarily confer delineated benefits and obligations on both sides. E.g., *531Carrig v. Gilbert-Varker Corp., 314 Mass. 351, 357-358 (1943). But here, nothing in the record shows a distinct consideration in return for child support apart from the core, unenforceable promise to coparent. Therefore, any implied promise that the defendant made respecting child support is inextricably linked to her unenforceable promise to coparent the child, and is similarly unenforceable.10
b. Equity power of the Probate and Family Court. The plaintiff and the dissenting Justices do not rely exclusively on contract theory, but also invoke the equity powers of the Probate and Family Court, arguing, as the dissent puts it, that “[t]he existence of an agreement to support on the part of the defendant, buttressed by society’s interests (as expressed through our statutes and our case law) and the best interests of the child standard, requires relief here.” Post at 538. Although the dissenting justices acknowledge that “our statutes offer the plaintiff no remedy, because the defendant is not a legal parent,” id. at 536-537, they would nevertheless enforce a support obligation by hypothesizing the Legislature’s probable intent, and invoking the Probate and Family Court’s general equity power and its mandate to care for and protect the “best *532interests” of children. Id. at 537-538. This argument, however informed by genuinely good intentions, misapprehends the extent and purpose of the Probate and Family Court’s equity powers. The equity powers conferred by the Legislature on the Probate and Family Court are intended to enable that court to provide remedies to enforce existing obligations; they are not intended to empower the court to create new obligations.
The duty to support a minor child is statutory. L.W.K. v. E.R.C., 432 Mass. 438, 443 (2000). Gediman v. Cameron, 306 Mass. 138, 140 (1940), and cases cited.11 See, e.g., G. L. c. 208, § 28; G. L. c. 209, § 37; G. L. c. 209C, § 9. A parent’s duty to support his child financially has existed by statute in some form since as early as 1692. Commonwealth v. Chase, 385 Mass. 461, 469 (1982); Province Laws 1692-1693, c. 18, § 5. Over time, the Legislature has created a comprehensive statutory scheme governing child support, see Orlandella v. Orlandella, 370 Mass. 225, 227 (1976), imposing that duty on a person who acknowledges paternity or is adjudicated the father. Commonwealth v. Chase, supra. The dissent highlights statutory language that “dependent children shall be maintained, as completely as possible, from the resources of their parents,” post at 536, but ignores that the Legislature has reserved this duty for parents. See L.W.K. v. E.R.C., supra at 444 (“parents have an obligation to support their minor children”).
The Legislature has identified those persons who are liable as parents to support their children. See, e.g., G. L. c. 209C, § 1 (person who is adjudicated father of child bom out of wedlock); G. L. c. 210, § 6 (person who adopts child). In addition, G. L. c. 46, § 4B, provides that, if the spouse of a woman who undergoes artificial insemination consents to the procedure, that spouse is considered the legitimate parent of a resulting child, and is thus obligated to pay child support. But the Legislature has not addressed the situation, present in this case, where a nonmarital cohabitant consents to such a procedure. This absence of legislative action is not a nod in our direction.
*533Here, the defendant is not a parent of the child under any statutory provision. She has not become a “de facto” parent by virtue of a long-term relationship with the child. Contrast E.N.O. v. L.M.M., 429 Mass. 824, 830 (1999); Youmans v. Ramos, 429 Mass. 774, 776 (1999).12 Apart from the unenforceable contractual obligation found by the Probate and Family Court judge, the defendant is legally a stranger to the child. Because the defendant is not a parent under any of the statutory provisions enacted to establish parenthood, she has no duty to support the child financially, and she may not be ordered to pay child support.
Because nonparents have no duty to pay child support absent a statutory duty, equity does not provide a remedy in this case. “It is a maxim that equity follows the law as declared by a statute.” Rossi Bros. v. Commissioner of Banks, 283 Mass. 114, 119 (1933). 2 J.N. Pomeroy, Equity Jurisprudence § 425 (5th ed. 1941). The “grant of equitable powers does not permit a court to disregard statutory requirements.” Freeman v. Chaplic, 388 Mass. 398, 406 n.15 (1983). Equitable principles cannot be used to create a duty to pay child support where the law does not recognize a legally cognizable parent-child relationship. Cf. C.M. v. P.R., 420 Mass. 220 (1995) (visitation). Similarly, we cannot infer that a void in the comprehensive statutory scheme that imposes an obligation of child support on parents authorizes us to fill that void by legislating an outcome that suits us. See Alguila v. Safety Ins. Co., 416 Mass. 494, 499 (1993) (circumstance not accounted for in statute does not permit judicial legislation).13 Equity is not an all-purpose judicial tool by which *534the “right thing to do” can be fashioned into a legal obligation possessing the legitimacy of legislative enactment.
Similarly, the “best interests of the child” is not a free-floating concept that empowers probate judges to impose legal obligations on people who have no legal obligations to begin with. The Legislature has specifically defined when the “best interests of the child” standard is to be applied and has tailored the factors to be considered, depending on the nature of the proceeding. See, e.g., G. L. c. 210, § 3 (c) (granting petition for adoption without requiring parental consent in certain circumstances); G. L. c. 208, § 28 (care, custody, and maintenance of child after divorce); G.L. c. 119, § 23 (foster care).
It may be the case that a child is better off with two persons responsible for providing support than with only one such person, and that it will always be in the child’s “best interest” to impose a support order on some second person. But that second person may not be imposed on, by way of equity or the “best interests” standard, until and unless the Legislature establishes that he or she is among a class of persons who have a legal obligation to the child. The “best interests” standard in and of itself is not a mechanism by which courts may reach beyond the law to obtain an equitable result. See, e.g., Commonwealth v. Leno, 415 Mass. 835, 841 (1993).
In response to the Probate and Family Court judge’s report of the matter, we conclude that “parenthood by contract” is not the law in Massachusetts. This case is remanded to the Probate and Family Court for further proceedings consistent with this opinion.
So ordered.
The breach of oral contract claim was added by an amended complaint filed on September 20, 2001. The initial complaint also included counts for “Application of [G. L. c. 209C, § 1,] to Determine Support Obligation” and “Equal Protection.” The judge entered summary judgment for the defendant on these counts.
The consent form, among other things, memorialized the parties’ agreement to hold the clinic and its personnel harmless for the support of any child bom as the result of procedures performed there. Both the plaintiff and defendant signed the form in the space labeled “Recipient.”
The clinic “consent form” is not a written contract between the plaintiff and the defendant, for its primary purposes were to explain the risks of the insemination procedure and to define the couple’s legal relationship as a unit with the clinic. See A.Z. v. B.Z., 431 Mass. 150, 158 (2000). That form does not state, nor does the record show, that the parties intended it to act as, or be a part of, any binding agreement between them. See id.
We do not address the issue of consideration but assume, without deciding, that there was consideration for this contract.
The dissent agrees that the judge permissibly could have found that the defendant entered into an agreement with the plaintiff “to create a child,” and *528sets out a portion of the judge’s findings in an Appendix. Post at 535. However, the dissent has not included in this Appendix other findings by the judge, such as the defendant’s earlier refusals to become a parent, her mental health issues, and the judge’s findings that there was no written agreement and neither an adoptive nor biological relationship between the defendant and the child.
We disagree with the dissent’s assertion that “parenthood by contract” would weaken the “best interests” standard. Post at 535. Where a person’s obligation to support a child is established, a court uses the “best interests” standard to measure whether and how that obligation is being fulfilled. However, this standard is irrelevant unless and until the person in question has a legal relationship to the child. Here, where there is no legal relationship (other than an unenforceable contract), the “best interests” standard does not come into play.
In A.R. v. C.R., 411 Mass. 570, 575-576 (1992), we stated that “[i]t may be that, as a matter of public policy, an affirmative duty to support, perhaps based on an express or implied promise, should be recognized on the particular facts of a case . . . .” Ibis proposition does not apply to the present case. The context of the quotation is a discussion of promises that a putative father may make to a child, not to the biological mother, by voluntarily undertaking a support obligation and then holding “himself out as the father to the child and to the world.” Id. at 575. See Liebson v. Liebson, 412 Mass. 431, 433-434 (1992) (defendant, who had voluntarily supported and lived with his wife’s niece for eleven months, and who shared joint physical custody of niece during that period, was not equitably estopped from denying support obligation after divorce).
Concluding, as we do, that there was an implied contract to create a child but that it was unenforceable, we need not address the plaintiff’s promissory estoppel argument. The same public policy considerations apply to this alternative theory of recovery.
In light of our conclusion that a contract to become a parent is unenforceable as against public policy, we do not consider the defendant’s contention that such agreements must be in writing. Although our past cases evince a preference for written contracts between unmarried cohabitants, see, e.g., Wilcox v. Trautz, 427 Mass. 326, 330 (1998), we have never announced such a requirement, and we decline to do so here.
The dissent’s conclusion that “parenthood by contract” is not the law, yet that a separate support obligation may nevertheless be imposed on a nonparent, is conspicuously silent on the possible ramifications of such a conclusion. See post at 535-536. Given the unprecedented nature of imposing a long-lasting support obligation independent of parenthood, we have no recognized legal principles for determining the defendant’s status. For example, although the defendant voluntarily ceased visitation, would she have visitation rights, or some right to resume contact with the child, that she could seek to enforce? While presumably not having a right to custody, would she have any say in some aspects of the child’s care, or at least in those aspects that would profoundly affect her own financial obligations (e.g., the decision to send the child to private as opposed to public school)? What if the plaintiff marries and her spouse wants to adopt the child? With an adoptive second parent to provide support, would there still be a basis for continuing the defendant’s obligation? What if the plaintiff dies, or becomes incapable of caring for the child? Would the defendant then have the obligation (or the right) of full custody? Given the novel and unprecedented status the defendant would have under the dissent’s theory, the Probate and Family Court would be called on to supervise the relationship between the parties and the child for many years to come, and none of them would fully comprehend their rights and obligations until each such right and obligation gave rise to a disagreement and was later defined by way of litigation.
At common law, a father having sufficient financial ability was bound to support those of his children who lived with him. Creeley v. Creeley, 258 Mass. 460 (1927).
To date, we have not considered whether a “de facto” parent has an obligation to support a child, and we express no opinion on that issue. We merely point out that the defendant had no relationship with the child and would not qualify as a “de facto” parent.
The dissent cites to the American Law Institute’s Principles of the Law of Family Dissolution: Analysis and Recommendations § 3.03(1) (2000), which recommend imposing parental obligations by agreement even where the person may not be a parent under State law. Post at 539-540 & n.4. While § 3.03(1) would provide some definition limiting the types of persons who could potentially be subject to an order of support, the articulation of the factors to be considered concludes with the open-ended invitation to base a support order on “any other facts that may relate to the equity of imposing a parental *534support duty on the person.” Principles of the Law of Family Dissolution: Analysis and Recommendations, supra at § 3.03(2)(d), at 415. Given the elusive nature of this definition, and the magnitude of the obligations being imposed, the task is better left to the Legislature and not to individual judges.