On April 18, 1984, R.R.K. filed a complaint with the Probate and Family Court for Berkshire County. The complaint alleged that he is the father of a female child bom to S.G.P. on July 23, 1981. R.R.K. requested that the court order that she allow R.R.K. visitation rights with the child. S.G.P.’s answer denied R.R.K.’s paternity and asserted as an affirmative defense that the child was conceived during her lawful marriage to her former husband. S.G.P. then moved to dismiss the complaint.
*13On June 6, 1984, the judge allowed R.R.K.’s motion to order R.R.K., S.G.P. and the child to submit to a blood test to determine paternity. The judge also allowed R.R.K.’s motion that he, S.G.P. and the child undergo psychological evaluation.
After the results of the blood test and psychological examination were submitted to the judge, an order was entered in October, 1984, granting R.R.K. some visitation privileges during the pendency of the litigation. The order explicitly recognized that it was without prejudice to S.G.P. A few months later, in January, 1985, a hearing was held on R.R.K.’s motion for visitation rights. The judge ruled that R.R.K. be permitted to visit the child once a month. R.R.K. was also required to pay $25 a week as child support.
After our decision in P.B.C. v. D.H., 396 Mass. 68 (1985), cert. denied, 475 U.S. 1058 (1986), S.G.P. filed a motion to dismiss on the ground that R.R.K. lacked standing to have the court adjudicate his paternity claim. The motion was heard in December, 1985, and allowed in March, 1986. R.R.K. appeals from the dismissal of his complaint. We took the case on our own motion.
The motion to dismiss filed by S.G.P. appears to be based on Mass. R. Dom. Rel. P. 12(b)(6), which provides for dismissal of a complaint for failing to state a claim on which relief may be based. The motion to dismiss avers that the child is a child of the marriage of S.G.P. and her husband (not a party to the action) “being conceived [in] wedlock at a time [when S.G.P.] was having marital relations with her lawful husband.” By this action, the motion continues, the plaintiff seeks to bastardize the child of the defendant’s marriage to her husband.
The complaint must be examined to determine whether it is legally sufficient, i.e., whether the plaintiff can prove some set of facts in support of his claim which would entitle him to relief. Nader v. Citron, 372 Mass. 96, 98 (1977). In making his ruling, the judge must take the allegations of the complaint, as well as such inferences as may be drawn, to be true. Id.
In examining the complaint under these guidelines, we discover that the plaintiff says (after the necessary geographical *14allegations) that S.G.P. gave birth to a child on a certain date, that he is the biological father of such child, that he has regularly and frequently visited the child, that S.G.P. now refuses to permit him to visit the child and that such visits are in the best interests of the child. We think that it was error to allow S.G.P.’s motion to dismiss.
We remand the case to the trial judge. He may make findings of fact and decide the case on the merits, or he may determine it appropriate for summary judgment and in this connection he may consider the affidavit of R.R.K. To assist the trial judge in whichever direction he decides to proceed, we make the following observations.
A guardian ad litem should be appointed for the child. Joinder of the former husband of S.G.P. as a party may be helpful but, if he continues to reside outside of the Commonwealth, the acquisition of jurisdiction and service of process may pose problems.
The case of P.B.C. v. D.H., 396 Mass. 68 (1985), is distinguishable. At the time of the commencement of that action the mother and her husband had remarried each other after their divorce and the child was part of an intact family. The husband in P.B.C. (unlike the former husband in the instant case) accepted the child and the child’s birth certificate lists the husband as father. In the instant case, the former husband’s name does not appear on the birth certificate. In the present case, the former husband has never recognized the child, and R.R.K. visited the child frequently until prohibited by S.G.P. The child called R.R.K. “Daddy.” In P.B.C., we insisted that the holding was limited to the circumstances of that case.
For guidance to the trial judge in deciding on remand whether to allow a motion for summary judgment for which reliance is placed on the affidavit of R.R.K. or in deciding the case on the merits, we point out that the human leukocyte antigen white blood cell test which was ordered and completed in this case is not conclusive or even admissible without other evidence tending to show a sexual alliance between R.R.K. and S.G.P. Commonwealth v. Beausoleil, 397 Mass. 206, 220 n. 18 (1986). G. L. c. 273, § 12A.
*15Finally, we speak to the issue of the presumption of legitimacy. The provenance of this presumption is the case of Goodright v. Moss, 2 Cowp. 591, 592 (1777), in which Lord Mansfield announced the rule that where legitimacy of a child bom in lawful wedlock is in issue, “the declarations of a father or mother cannot be admitted to bastardize the issue bom after marriage.” The mie has acquired the name of the author of the opinion and it has been extended to a child conceived as well as bom during lawful wedlock. State v. Bowman, 230 N.C. 203, 204-205 (1949). Wigmore severely criticizes the mie. 7 J. Wigmore, Evidence (Chadboum rev. 1978).
As early as 1861, this court announced that there is a legal presumption that a child bom in lawful wedlock is legitimate but that such presumption may be rebutted by proof either that the husband had no access to the wife during the time when, by the course of nature, he could be the father of the child or, alternatively, that he was impotent at the time. Hemmenway v. Towner, 1 Allen 209, 209-210 (1861). See Taylor v. Whittier, 240 Mass. 514, 516 (1922) (impotence). Such proof must be beyond a reasonable doubt. Phillips v. Allen, 2 Allen 453, 454 (1861).
The case is remanded for further proceedings consistent with this opinion.
Judgment reversed.