No, the beginning point is "choose to engage in the one activity that can result in pregnancy, or choose not too".
It is like getting drunk. "do you choose to drive anyway, or do you call a cab".
Like the gasoline fight in the movie 'Zoolander'. "should we light cigarettes now, or change our clothes and shower the gasoline off first".
Like Baldwin. "check the gun first, or just point and pull the trigger".
Once you make a decision, consequences begin to spring from that. Then, you make further decisions, to mitigate the results of the previous decisions.
Logically, the only way to guarantee no pregnancy, is no male female sexual intercourse. If you choose to take the risk, then that is what you chose; your choices should now be limited, based on the choice you already made. It should be raise to adulthood, or give up for adoption in the average case. Basing a general law on extreme cases, leads to bad laws. Extreme cases, can be judged differently, but those are rare.