They place in different race families constantly. It is illegal to consider race when placing a child for a foster placement.
It may be illegal but I know for a fact that it happens. I work with a woman who got a 5 day old black child(she's white) and when she was going for an adoption(child's mother gave her up in the hospital) the case worker didn't like the idea of a single white woman adopting a black child. Even in our case right now, the demeanor of our case worker seemed to change and her want for the baby to go back to his family changed after she found out we were interested in adopting him. He's Mexican and we're not Hispanic.