I've had the same worries for 3 yrs. now.
But, I now have 4 males and just got a little female. I don't want to breed, so I have no other choice. Also, my oldest male, JPop, has become pretty agressive toward 1 of my males. Too much testostrone floating around. Just hope neutering solves, or at least helps this problem. They were scheduled for next week, but I think I'm going to have a conflict at work, so I'll have to reschedule.