There are orphaned children, and adoption, no? So homosexual unions that are legally recognized will be of benefit to child rearing. I'll brace myself for the homsexuality/pedophilia connection that many are in love with making around here.
As far as your other argument about black conservatism, while its true that black folks do lean conservative, we've pivoted against the right, politically, because we know the ideology is attempting to reproduce the white supremacy, anti black constructions that are a function of traditional america, so we dont vote republican. Its a shame that some black folks dont extend that same sense of advocacy to other groups, but thats my disappointment with the human condition in general.
Stop trying to compare someone's Sexual lifestyle with race. We have plenty of laws that tell people what they can and can't do when it comes to sex.