Ok, sounds like you are one of the younger members if you're talking about your dad doing something about the neighbor's dog so I will answer your question a little more gently than some of the other posts sounded (not that I disagree with what they said though).
Your dad is correct in that he doesn't want to cause problems. Unless you are willing to help put up fences to make sure your dogs can't get out, you really can't point a finger at your neighbor's dog that comes over because yours wander too. Having an unspayed female means you have to take responsibility for any litters that happen because you chose not to spay her. If you are not a breeder than she should be spayed, it's much better for her health and solves the puppy problem as well. If you are really far away from any clinic that will offer inexpensive spaying, you're going to have to keep her confined in a garage or the house till she's out of heat till you can afford to get her spayed.
As far as your neighbor's dog roaming, let me ask you this. If you didn't have a female that kept getting pregnant by this dog, would it bother you to have him coming onto your property? The fact that your neighbor's dog is intact is not as important because even if he was, you would still have to deal with the possibility that she would get pregnant by another intact stray dog. Simply because you haven't seen one come around when she's in heat, doesn't mean they don't and wouldn't make puppies if the neighbor's dog hadn't beaten them to it.
Your dad is correct in that he doesn't want to cause problems. Unless you are willing to help put up fences to make sure your dogs can't get out, you really can't point a finger at your neighbor's dog that comes over because yours wander too. Having an unspayed female means you have to take responsibility for any litters that happen because you chose not to spay her. If you are not a breeder than she should be spayed, it's much better for her health and solves the puppy problem as well. If you are really far away from any clinic that will offer inexpensive spaying, you're going to have to keep her confined in a garage or the house till she's out of heat till you can afford to get her spayed.
As far as your neighbor's dog roaming, let me ask you this. If you didn't have a female that kept getting pregnant by this dog, would it bother you to have him coming onto your property? The fact that your neighbor's dog is intact is not as important because even if he was, you would still have to deal with the possibility that she would get pregnant by another intact stray dog. Simply because you haven't seen one come around when she's in heat, doesn't mean they don't and wouldn't make puppies if the neighbor's dog hadn't beaten them to it.