Explaining donor insemination to a kid can be a little tricky—"See, there was this man, and he went into a little room. . ."—and some parents may choose not to tell the little ones at all. Researchers at a fertility clinic that is in favor of openness looked at family dynamics to find out whether it's good for kids to know that half their DNA came from a stranger.

What the researchers wanted to know: Are kids who know their biological daddy isn't the daddy around the house better adjusted? (Does the strain of keeping that deep secret show?)

What they did: Families whose encounters with the King's College Hospital Assisted Conception Unit in London had resulted in a donor-insemination child between the ages of 4 and 8 were invited to participate in the study, and 46 of the 60 families contacted agreed. Of the group, 18 "disclosers" had told their child or intended to in the future; the 28 "nondisclosers" had decided against telling their child or were undecided. The study's lead author, a psychologist, visited each family twice. At the first visit, she talked to the parents about their children's development and the quality of various family relationships, and handed over questionnaires for parents and teachers to fill out. At the second visit, she gave each child a puppet interview, in which two puppets say things like "I am clever" and "I am not clever" and the interviewer asks the child, "How about you?"

What they found: Nondisclosing mothers described their children as more of a strain than did disclosing mothers, and also argued more frequently with their children than disclosing mothers. There was no difference for fathers on either of those characteristics, though, and on most characteristics, the groups were the same—like the parents' warmth toward their children, parent-child interaction, and how much the parents criticized the child. Nondisclosing mothers reported more conduct problems in their children. But fathers and teachers didn't, and the kids were the same on other aspects of social adjustment, such as hyperactivity and problems with peers.

What the study means to you: This offers some evidence that disclosing mothers have better relationships with their children; maybe the secrecy does create tension.

Caveats: Maybe mothers who chose openness are just more relaxed about parenting. Many of the families who refused to participate said it was because they were keeping the donor insemination a secret and didn't want any chance their child would find out about it—so the nondisclosing families in this study probably don't represent the most secretive nondisclosers.

Find out more: Oprah did a show on donating sperm: www.oprah.com

Read the article: Lycett, E., Daniels, K., Curson, R., and S. Golombok. "Offspring Created as a Result of Donor Insemination: A Study of Family Relationships, Child Adjustment, and Disclosure." Fertility and Sterility. July 2004, Vol. 82, No. 1, pp. 172–179.

Abstract online: www.fertstert.org