Only two problems.
1.)Equal risk. When a woman becomes pregnant the risks to her is very clear. But where is the risk to the men? Does the men get something growing inside of them? Do the men have the medical problems associated with pregnancy? When a man and a woman have sex, the woman has 100% of the risk every time she has sex. With out child support there is zero risk to the male. When you are trying to figure out how to divide up responsibility, you need to apply equal risk with the law. When you decide that child support is a choice, you are saying that the risk to the female becomes 200% and the risk to the male become zero. Even if the female never had a choice about having sex, she would still have 200% of the risk.
2.) Once the egg is fertilized, it is 100% dependent on the mother. With out the mother there is zero chance of survival. The decision of not allowing the egg to continue to survive is 100% of to the mother, the doctor, and her support network. 100% of all abortions happen for only one reason, the lack of a support network. If the father wants to stop the abortion, there is only two options, provide a support network for the mother, or take the fertilized egg out of the mother and find a different host.
When a woman gets pregnant, she has no choice in her life on what is going to happen (with out laws). All she can do is direct the outcome to a better end for her. When a guy gets pregnant, he has 100% control over his life from that point on (with out laws). Laws are written so the parties in all endeavors shares equal risk from the outcome. When one party has "skin" in the event, the other has to offer equal "skin".