Gay' family kids 7 times more likely to be homosexual
Not that I'm endorsing the Church's position here or even ostensibly supporting Zeb's position, but at least one study seems to suggest that openly gay parents may have some influence on the child's sexuality. Now, whether that's a "non-genetic" cause as Zeb alludes to (what is that exactly? "catching the ghey" like some cold or flu?) or, that those children are more open to other sexuality because they feel the support to declare such is clearly open to question given the stigma that still exists today for homosexuals.
Now, in fairness to forelife's point, we must contrast the above to the long-term outcome of children in the foster care system. Children in the foster care system "experience higher rates of physical and psychiatric morbidity than the general population...they were found to have double the incidence of depression, 20% as compared to 10% and were found to have a higher rate of post-traumatic stress disorder (PTSD) than combat veterans with 25% of those studied having PTSD. Children in foster care have a higher probability of having Attention Deficit Hyperactivity Disorder, and deficits in executive functioning, anxiety as well other developmental problems...higher degrees of incarceration, poverty, homelessness, and suicide."
Sounds to me like a qualified homosexual couple might be a pretty positive trade-off when comparing the long-term outcome of children in the foster care system to the dubious chance of them "catching the ghey".
That said, I take no position relative to whether such adoptions and such should be allowed and I am not putting forth any personal position on gay marriage.