First--I know who makes the decision legally. That's obvious enough--who holds the legal responsibility. Though, I'm not so interested in legality here as who is behind the scenes urging the woman or girl to dispose of an inconvenience and applying pressure. I point, also, to recent media murderings of women who have a pregnancy inconvenient for some man.
Now, I understand where you are coming from, however, the woman has the only say-so in the matter, really.
Sure, the "dad/doner" can push, cajole, whine, threaten, etc., but the woman is the one who has the abortion. She's the one that signs "on the dotted line", so to speak.
I'm not saying someone isn't coerced into it, but just like the "One is Enough" story, (in reverse, actually), the final 'authority' lies with the woman. This from my male perspective, at any rate.