If, for whatever reason, it has become too difficult to let go of the anger and toxicity you harbour against your baby daddy or mama, shield that part from your child. As you show him how men are trash, or that women are there to be belittled, go to bed knowing he/she too is growing into a wo/man.
Essentially, you are feeding the world with another toxic human in the name of settling your scores. And this toxic human is carrying your blood. So stop being an imbecile and keep children out of your anger; they are innocent.