Its tough with an intact male because essentially you will always end up with more babies, and you will most likely always have to rehome/adopt them out until you neuter him. Males generally fight with other males after puberty. Although there are always rare circumstances where that is not the case, people generally take the precautionary route and separate them, because often times there's no way to know until its too late. With females you've already stated the obvious inbreeding problem, and thus they would always need to be separated/rehomed/adopted out as well. Its an endless cycle of parenting for you if you choose not to neuter him, and if you do then you could always keep your little girl. Best of luck!