Depends on how underhanded or not you want to be.
Firstly, consider alternatives to abortion. There's adoption, not just by complete strangers, but by family too that would be in a good position to look after the kid.
You have two tactical choices: Negotiation or Action. The legal and moral implications of Action varies. I'll give you all of the possibilities that I can think of; I'm not endorsing any particular choice, as only you can make that choice.
Discuss the matter with her. I'm willing to wager that niether of you are in a good position for parenthood. Play the fact that the child's quality life will be poor because you're not in a position to look after it. Don't just say "I don't want a kid 'cos".
This would likely have better results: Tell her that you dont want to have a future relationship with her; but that you are
dead serious about having 50% custody. Then you will not have to pay her sanything and she will not want your next girlfriend helping you raise "her" child.
Threats upon yourself could (depending on the woman) spur action. If she is a semi-serious thing, this will probably produce very effective results. State that you'd prefer suicide or harm to becoming a father. You have to be very serious about this if this is the course of action that you want to take, as it's very much an all-or-nothing course of action. Actually buy a couple of things that you can commit suicide or harm yourself with, make sure that she sees them; or if you really want to drive the point home, make a botched (rigged-to-fail) attempt. Of course, there are dangers in actually harming yourself, and it might hurt a lot.
You can spur an abortion yourself by placing a good quantity of water-soaked cotton-wool into her vagina.
Lastly, and least legally, a very hard impact with a blunt object to the stomach will almost certainly accomplish the fact. You run a very big risk of prosecution and serious injury to your partner.
Bronxtal112 said:
Step up to the plate and be a man. Keep the baby and marry her.
Life is a beautiful thing. Some people would do anything to have their own baby.
Going back to the adoption point, you could very well give that "some people" their own baby.
And finally, a good couple of paragraphs courtesy of google:
Answers.com said:
Ultimately in is her decision as she is the one that is carrying and giving birth to the child however, it should be a decision you can make together. You cannot convince or force anyone to feel a way they don't and in this case abortion is a huge decision - if she does not want to get one or believe in them you are going to have to respect her decision.
If you intend on being with her you are going to have support her in any way possible - the less stress the better. If you do not want a child unfortunately it is too late for that now and made that decision when you decided to have unprotected sex. You are going to have to decide what you want and if you are going to leave her and don't want your child (which is a huge decision) you should discuss your options with her.
In the end you both are going to have to decide what is best for you both and you should talk. It may help to consult with a doctor, counsellor or religious leader that can help you with all aspects of your decision.
If both of you do not feel ready for raising a child then giving the infant up for adoption is a widely accepted alternative to abortion. Again this is a decision both of you must take.