Less research has been done on children in families headed by gay men, but data collected as part of the National Longitudinal Lesbian Family Study have shown few differences in psychosexual development, psychological adjustment and overall well-being.

"Boys seem to do as well as girls," said Dr. Nanette Gartrell, associate clinical professor of psychiatry at University of California, San Francisco and principal investigator in the 23-year study.

"Most offspring of same-sex parents are heterosexual as adults," she told ABCNews.com. "By the time our study kids were 10 years old, they demonstrated a sophisticated understanding of diversity and tolerance, and an appreciation of the destructive effects of discrimination."