Technically, if someone fosters a child (unless it's long term) then they're not "raising" the child.

They're "giving them a place to stay".

Not that the latter is bad or any less noble. But let's not kid ourselves into believing that any couple (gay or straight) could raise 100 children through fostering because they're not there for 16 years. If they were literally raising 100 children, they'd need a hell of a big house and can you imagine the line for the bathroom?