Children usually benefit from having two parents instead of one.
The gender of each parent, however, does not have a significant impact on a child's success.
This finding strikes at the heart of one of the major arguments of gay marriage and adoption opponents.
In a finding that confronts deeply rooted beliefs about parenting, a new study concludes that parents' genders have little impact on children -- suggesting that same-sex couples are as effective at raising children as heterosexual couples.
On average, children succeed most when raised by two parents rather than one. The parents' genders, however, make little difference in terms of a child's development, according to a landmark study published in the Journal of Marriage and Family.
The analysis of 81 parenting studies by sociologists Judith Stacey of New York University and Tim Biblarz of the University of Southern California challenges the widely held notion that children need both a mother and a father in their household in order to thrive.
"What we're saying is there is no best (household) structure," said Stacey, a professor of social and cultural analysis at NYU. "There are better parenting practices, and certainly better relationships and worse relationships, but they don't come in one particular structure."
Many of the studies that highlight gender-specific parenting skills, such as a father's masculine interactions with sons and a mother's nurturing care, only compared heterosexual married couples with divorced or single-parent families. Lesbian- and gay-parented households as well as single adoptive parents were usually left out.
By not controlling for the number of parents, sexual identity, marital status and biogenetic relationship to the children, the research often failed to isolate the real impact of gender on effective parenting, according to Biblarz and Stacey's study.
Recent research on lesbian-parented households seems to support the study's gender-neutral thesis. Overall, studies indicate that children raised with lesbian co-parents do just as well as children raised by heterosexual married couples. The children of lesbian co-parents may even have fewer behavioral problems and higher self-esteem.
In addition, single-mother households correlate to lower child delinquency rates, greater parental control and higher educational performance than single-father families.