(dissenting, with whom Marshall, C.J., and Spina, J., join). The court reasons that the term “consanguinity,” G. L. c. 272, § 17 (incest statute), cannot be read together with G. L. c. 207, §§ 1 and 2 (marriage prohibition statutes), with the startling result that the defendant cannot be prosecuted for having sexual intercourse with his stepdaughter. Despite the self-definition in the incest statute by means of express reference to, and incorporation of, the marriage prohibition statutes, the court strives to examine a plethora of sources to support its conclusion. The court’s analysis is faulty, both in law and policy, for the reasons now described that persuade me that the defendant’s sexual intercourse with his stepdaughter can be prosecuted as incest.
1. It is self-evident, as mentioned above, that the incest statute creates the definition of the crime within its own terms by expressly referring to, and incorporating, the marriage prohibition statutes. This alone should end the inquiry. But any doubt on the matter is settled by the following.
(a) In Commonwealth v. Smith, 431 Mass. 417 (2000), we concluded that the words “sexual intercourse” in the incest statute were limited to penile-vaginal penetration but did not cover unnatural sexual intercourse. In construing the statute, we stated that “ ‘[pjersons within the degrees of consanguinity’ to whom the [incest] statute’s prohibitions of intermarriage and sexual intercourse apply are not limited to blood relations, but *288include also certain affinai kin as well as stepparents.” Id. at 422. We carefully explained why this is, and should be, so:
“The Legislature’s purpose in criminalizing incestuous conduct must thus extend beyond the prevention of genetic defects, as this goal would clearly not be advanced by criminalizing marriage itself, without more, between blood relations, and still less by prohibiting coitus between affinal kin who do not share a common bloodline. See Model Penal Code and Commentaries § 230.2 comment 2(b), at 403; comment 3(b), at 412-413 (1980). Indeed, the scope of the incest statute, as it relates to both conduct and persons, strongly suggests that its framers valued and sought to promote the sanctity and integrity of familial relationships, as well as to protect children within the family from sexual impositions by their elders. See, e.g., id. at § 230.2, comment 2(c)-(e), at 405-407, and authorities cited; Commonwealth v. Fouse, 417 Pa. Super. 534, 538 (1992).”
Id.
Two years after the Smith decision, the Legislature rewrote the incest statute to broaden the sexual conduct prohibited to include unnatural sexual intercourse. See St. 2002, c. 13. The amendment was in direct response to the Smith decision. No change was made in the definition of incest contained in the statute. It is obvious from this that the Legislature accepted the definition stated in the Smith case, and expressed agreement with the language therein explaining the purpose of the statute. Far from being dicta, the quoted language is a critical part of the court’s analysis and is to be accepted for its substantive content.
(b)(i) The court refers to the legislative history of the incest statute in an effort to support its conclusion. Ante at 281-284. But, ultimately, the court concedes, as it must, that there is nothing there because the Legislature’s reason for not inserting the word “affinity” in R.S. (1836), c. 130, § 13, is unknown. Ante at 283-284. It can be said, from the language of that statute, that doing so was unnecessary in light of the statute’s language, applying to “persons, being within the degrees of consanguinity, within which marriages are prohibited,” and to “persons” whose marriages otherwise are “declared by law to be incestuous and void.” R.S. (1836), c. 130, § 13. Further, the court *289completely ignores the historical character of the statute, see Commonwealth v. Ashey, 248 Mass. 259, 260 (1924), which ultimately enforced “the Levitical decrees,” that applied the prohibition against incest to relationships of affinity. See 2 C. Torcía, Wharton’s Criminal Law § 242 (15th ed. 1994) (explaining that doctrine of affinity grew out of canonical maxim that husband and wife are one); Metteer, Some “Incest” is Harmless Incest: Determining the Fundamental Right to Marry of Adults Related by Affinity Without Resorting to State Incest Statutes, 10 Kan. J.L. & Pub. Pol’y 262, 273 (2000) (explaining that incest prohibition under law of Leviticus extended to relationships by affinity).
(ii) The court also cites to various statutes to argue that the Legislature views the terms “consanguinity” and “affinity” as distinct. Ante at 276-277. Thus, the court reasons that, by employing the term “consanguinity” in the incest statute, the Legislature intended to limit the statute’s reach to relationships of consanguinity only. Ante at 277-278. The use of the terms “consanguinity” and “affinity” in other statutes does not resolve the present issue concerning the interplay of the specific statutes with which we are concerned. If the Legislature had intended to limit the incest statute’s reach only to relationships of consanguinity, it could have done so by leaving out any reference to the marriage prohibition statutes, instead of choosing, as it did, to supplement the incest statute by expressly incorporating the marriage prohibition statutes into that statute’s reach.
(iii) The court’s references to the laws of other States shed no light on the answer to the reported question. The main point, of course, is what our statute actually does, but it is worth noting that Massachusetts is by no means alone in punishing affinai incest because of the crime’s destructive impact on the familial relationship. Twenty-eight States punish affinai sexual intercourse or sexual conduct of some kind.1
(c) The court places great emphasis on the Model Penal Code, *290which does not make affinai incest criminal. We have not adopted the Model Penal Code, although from time to time, we express agreement with principles expressed therein. That is precisely what was done in the Smith case, where the Code was cited as persuasive in stating that “sexual relations between stepparent and stepchild may have the same disorganizing impact on the family unit and the same destructive effect on the growth of the child’s personality as would incest between natural parent and child.” Model Penal Code and Commentaries § 230.2 comment 3(b), at 412-413 (1980). Indeed, as the Code candidly recognizes, “[t]here are valid reasons for prohibiting sexual relationships between stepparent and stepchild.” Id. at 412.
2. The court’s authority for its conclusions does not withstand rigorous examination, and it is wrong to use that authority to declare an act of the Legislature futile and meaningless in significant part. In the last analysis, the text of the incest statute, combined with the Smith decision, leaves no room to doubt the statute’s purpose and application.2 The court leaves us with a situation where this defendant will avoid prosecution for incest, and (unless the statute is changed) a stepfather can have consensual sexual intercourse with his sixteen year old stepdaughter without fear of criminal sanction. (But, he will not be able to marry her.) As a result of the court’s decision, we are left with an unfortunate state of affairs that frustrates legislative intent and undermines the value and stability of the family as the core unit of society. I dissent.
These State statutes are: Ala. Code § 13A-13-3 (1994); Ark. Code Ann. § 5-26-202 (LexisNexis 2003); Colo. Rev. Stat. § 18-6-301 (LexisNexis2003); Conn. Gen. Stat. § 53a-191 and § 46b-21 (2003); Del. Code Ann. tit. 11, § 766 (2001); Ga. Code Ann. § 16-6-22 (2003); 720 Ill. Comp. Stat. § 5/11-11 (West 2003); Iowa Code § 709.4 (2000); Ky. Rev. Stat. Ann. § 530.020 (Lexis 1999); Md. Code Ann., Fam. Law § 2-202 (1999) and Crim. Law § 3-*290323 (LexisNexis 2002); Mich. Comp. Laws Ann. § 750.520b (2003); Miss. Code Ann. § 97-29-5 (Lexis 2000) and § 93-1-1 (LexisNexis 2003); Mo. Rev. Stat. § 568.020 (1986); Mont. Code Ann. § 45-5-507 (2003); Neb. Rev. Stat. § 28-703 (1995); N.H. Rev. Stat. Ann. § 639:2 (West 1996 & Supp. 2003); NJ. Stat. Ann. § 2C:14-2 (West Supp. 2003); N.C. Gen. Stat. § 14-178 (2003); Ohio Rev. Code Ann. § 2907.03 (Baldwin 1997 & Supp. 2003); Oída. Stat. tit. 21, § 885, and tit. 43, § 2 (2001); Or. Rev. Stat. §§ 163.505, 163.525 (2001); S.C. Code Ann. § 16-15-20 (West 1985); S.D. Codified Laws § 22-22-19.1 (Michie 1998); Tenn. Code Ann. § 39-15-302 (LexisNexis 2003); Tex. Penal Code § 25.02 (West 2003); Utah Code Ann. § 76-7-102 (Lexis 1982); Wash. Rev. Code § 9A.64.020 (2002); W. Va. Code § 61-8-12 (Lexis 2000); Wyo. Stat. Ann. § 6-4-402 (LexisNexis 2003).
For this reason, the rule of lenity cited by the court has no application. See Commonwealth v. Welosky, 276 Mass. 398, 401-402 (1931), cert. denied, 284 U.S. 684 (1932).