One of the primary concerns regarding the breakdown of the married, two-parent family is the impact on children. There is no mistaking the majority of more than 30 years of social science research that indicates children do best on every measure of well-being when raised by their married mother and father. These studies clearly show this is the best possible environment for children to grow and thrive. Equally revealing is the research on the impact to children when the father-mother structure breaks down. Whether through divorce, cohabitation or same-sex "marriage," children in these circumstances fail to receive the full benefit of growing up with a married mother and father.
One key ingredient in a father-mother household is the presence and influence of two distinct genders – male and female. Research and common sense tell us that girls and boys need role models of both genders, but research further reveals that fathers and mothers contribute uniquely to their children. Dr. David Popenoe, author of Life Without Father: Compelling New Evidence that Fatherhood and Marriage are Indispensable to the Good of Children and Society, writes that, "The two sexes are different to the core, and each is necessary – culturally and biologically – for the optimal development of a human being."
Just as each gender is important for child development, the absence of one parent has implications for a child. For example, compared to children from intact homes, children of divorce are far more likely to struggle academically, live in poverty, engage in drug and alcohol use and other high-risk behaviors, commit suicide, and experience psychiatric problems and relationship failure in adulthood.
Cohabitation also presents increased risks for children. Most children in cohabitating homes live with their biological mother and not their biological father. Numerous studies find that children living in cohabitating situations are at increased risk for sexual and physical abuse and violence. The National Marriage Project warns, "The evidence suggests that the most unsafe of all family environments for children is that in which the mother is living with someone other than the child's biological father."
The same deficits for children present in divorced and cohabitating homes also exist in situations with two same-sex parents. The recent legalization of so-called same-sex "marriage" intentionally denies children either a mother or a father. It also sets up a direct conflict between an adult's right to parent a child on her own terms and the child's right, and best interest, to be parented by both a mother and a father.
Traditions and customs of marriage differ, but opposite-sex marriage has thrived across all cultures as the most optimal arrangement for nurturing the next generation of children and connecting them to their mother and father. Yet, same-sex "marriage" necessarily means that gender no longer matters, and either the mother or the father is treated as expendable to the child.
While there's plenty of data collected over a span of years showing the benefits of man-woman marriage to kids, long-term and replicable data on the effect of homosexual unions on parenting doesn't exist as this social "experiment" is still in the early stages.