Dave:
People who engage in sex (men or women) know that there can be consequences.
Thus, contraception is a shared responsibility.
Are you suggesting that men or women who have sex need not concern themselves with the natural consequences?
When it comes to the question of abortion, we're already past the point where any care for consequences of sex could make a difference. There's no point crying over spilled milk. The question becomes one of what to do now.
So, it is all right then to say "I choose to willingly engage in this act that, naturally, may lead to someone being dependent for its life on me. But I am under no obligation to take responsibility for my action that led to it. It has no rights anyway."
No. That's not all right.
A person who has decided to have sex has decided to risk conception. But that imparts no responsibility?
Men and women who find themselves in the situation of dealing with an unplanned pregnancy have responsibility to make a decision as to the future, whether or not they want that responsibility. The
moral obligation to carefully consider any decision to be made regarding the foetus lies with both parents.
In practice, though, there's an asymmetry. The woman is the one carrying the child. The man can run away from the whole matter if he is irresponsible. So, while the man can avoid taking positive action, the woman does not have that luxury. She must decide whether to bear the child or not to.
Moreover, the woman is personally at risk in carrying a child to term and birthing the child, whereas the man is not. Therefore, the woman has a strong claim that her interests should be paramount regarding the pregnancy and birth.
Of course, once conception has occurred, there is a third "potential person" in the mix - the unborn foetus itself. It has some interests as well, and those interests tend to become more significant as the pregnancy progresses and it comes closer to full personhood. However, in balancing the interests of the woman against those of the foetus, the woman's interests will generally dominate, especially if her health is put at risk by the pregnancy.
The ultimate decision as to whether the woman bears the child or not must be hers. Nobody else can have the final word on that. Certainly, the man is in no position to force her to decide one way or the other. He cannot make her a slave to his wishes.