HELP!! should I spay or neuter my rats?

I recently got two rats who I thought were both boys, but it turns out one's a girl and the others a boy. I don't want to get rid of either of them because I love them and I'm already attached. So I've been debating whether to just let them breed (even though they are siblings, and yes I do know the risks of inbreeding) or to get one of them fixed. I'm looking for an unbiased answer/opinion of which would be a "better" choice. My life style isn't that great to be raising a bunch of baby rats, but if I needed to I could do it. I also don't want to separate them because I got two so they wouldn't get lonely. I need help soon because they're about 4 weeks old and I don't want my little girl to get pregnant.