I'm not going to rent out my place to a small family.
Why do you not want to rent to a family?
Their small child is so noisy and unruly. They will be too loud.
It's not appropriate to deny rental applications on the basis of having a child. Families need places to live just as much as single people. You should compromise with the family and allow them to rent but also ensure that they keep the noise down to reasonable levels in order to not disturb any neighbors.
I don't care, I'm not renting to them. Who will defy me?
What you are doing is not right. At least give the family a chance to rent. What if someone denied you a place to live because of an attribute about you?