Rather than engaging in a they-said/they-said discourse, let's consider some facts:
Regnerus:Even is we set aside all of the biased sampling and flawed methodology, Regnerus does not prove, nor even suggest, that gay couples are not good parents. At face value, it suggests that children of traditional marriage who had one parent cheat on their spouse with a person of the same sex did not fare as well as their peers. Children of divorced parents probably fare similarly. Moreover, these are children who were born in a different era
The claims made about the Regnerus research are more flawed than the research itself which is profoundly defective.
Marriage:Regardless of whether or not society recognizes same-sex marriages, the same heterosexual couples will produce the exact same children. For the most part, gay and lesbian couples will continue to adopt kids, Surrogacy will remain very rare given the expense and legal risk. Some lesbian couples are conceiving children via sperm donation. Whether or not that will increase with marriage equality remains undetermined.
Gay parenting:According to the APA;
Beliefs that lesbian and gay adults are not fit parents likewise have no empirical foundation. .... The results of some studies suggest that lesbian mothers' and gay fathers' parenting skills may be superior to those of matched heterosexual couples.Furthermore, extensive research has determined that children raised by gay and lesbian couples are no different that the children of traditional marriage in terms of sexual identity and sexual orientation.