Someone Remind Me Where Foster Children Come From

So Florida ruled that banning gays and lesbians from adopting kids is unconstitutional. Yay! But reading some of what Florida's attorney general had to say about the ruling makes me wonder where some people think foster kids come from. I mean, you can't have a foster kid without having a kid first, and you can't have a kid without a woman and a man having sex. Right? With that said . . . .

"The attorney general's office had argued that gay men and lesbians are disproportionately more likely to suffer from mental illness or a substance abuse problem than straight people, rendering them less fit to parent -- especially children in foster care who already are under tremendous stress."

So straight people don't make foster children? Then where do foster kids come from? I think I might need to have "the talk" with my mother all over again.