I... was deeply hoping this thread was just some kind of troll.
...
I'm still not entirely sure it isn't.
That being said, watch me reply anyway!
Do I think there ought to be birthing contracts? Not a chance. Do I think the general masses need to be a little bit smarter about using protection? Actually yes. And do I think there need to be some changes made to the system, that prevents women from working guys over (in the not-so-happy way)? Absolutely. I just think your suggestion as to how to fix the problem is utter derp, that's all.
If you don't really want a child, then try your hardest not to encourage an unwanted pregnancy along. Take the pill. Use the condoms. Buy some spermicidal lubricant. All of the above. Or hey, do the best thing ever and just buy a chastity belt! Your woohoo goes nowhere near her whazzit. Safest sex ever. All the cool kids are doing it. And for the record, contrary to popular belief, it is not JUST the woman's job to make sure babies don't happen. That responsibility falls to the man, too. Do your part: Wear tight pants. It helps. ... Really.
And you know what? Sometimes, despite you doing everything RIGHT to prevent a pregnancy, it just isn't enough. Sometimes, it's not anyone's fault. It just happens. Forcing a woman to have an abortion as a result though...? That's so many shades of wrong there, buddy.
This isn't easy stuff. We're not talking about a trip to the dentist where you're in, you're out and you're on with your day (with a slight migraine and maybe a sugarfree lollipop.. strawberry, preferably). This is a serious decision and not one to be flippantly thrown around as being the answer for EV-REE-THRING. Abortions, in some cases, can destroy a woman's ability to have children ever again - period. It's painful. It's emotionally destructive. And it's something a lot of women never ultimately forgive themselves for doing. (Because you know. FYI, some people really honestly have religious beliefs and a moral compass that consider this stuff murder, which they do not merely whip out as an excuse to stick it to the men in their lives every chance they get. Just sayin.)
These are some hefty risks and I can't name a single woman who would be thrilled about being bound by legal documentation, pushed into making those choices. That's her body. She has to live with whatever ultimately happens, long after the act itself has been carried out. We're not just living incubators, you know. Sometimes, when things get broken inside, there's no way to fix them. Producing kidlets is something that is natural to the human body - forcibly removing them is not and there are consequences to that.
While we're on the subject, the abortion pill isn't much better. Do you know what the side-effects on that thing are? Among the charming pain/nausea/diarrhea line-up, you've also got bleeding so severe that without surgery to stop it, you'd best have a current restore point.
Now I don't know about any of the other ladies out there, but if my choices were suddenly reduced to "unwanted pregnancies with Mr. Fabulous must be terminated at the possible cost of my health BY LAWZ" or "keep the dang pants ON PLZ", guess what Mr. Fabulous is never going to get anywhere near? Do not pass whazzit. Do not collect sexytimes. Just no.
Then again, if your aim in this is to get people to start practicing a looooot more abstinence, then I guess sure. Achievement!