Fathers to be killed in exchange for the child to be born

Fathers? Crazy talk. It's the mother that has the ability to abort the child to prevent transgressing upon the law. Killing the father seems not just innapropriate but also extremely impractical. It means the father should kill any mother who doesn't abort the pregnancy at his request in order to save his own life. Not a desirable payoff structure.

An even worse implication of that means of enforcement - practical, legally sanctioned assassination.

• Paternity is far more difficult to trace than maternity. It is possible the father is not even aware that a child of his is gestating.
• Consider either woman with a grudge against a male enemy or a male willing to pay a willing baby-popping pseudo-assassin.
• Said woman simply needs to acquire sperm from the male. This is a relatively simple task in many instances. Options include:
  • Seduce intended victim yourself. Use faulty condoms and or lie about your own birth control status.
  • Seduce intended victim yourself, intentionally take semen from the used condom or neglect certain practical guidelines of use.
  • Pay someone to seduce the intended victim and acquire a sample for you.
  • Invade the victim's privacy with stealth and acquire semen produce during the victim's private sex life or even lack thereof. (Presumably just poisoning the guy while doing this would be too suspicious?...)
• Identify a willing or clueless cuckold that can think they are the parent until too late for it to matter.
• Sell your reproductive credit at the last minute.

If you create a system of rules they will be gamed. That rule is far too easy to game.