Are you this dense? If, theoretically, I was on a joint Car insurance scheme with someone, and let them use the car for a period of say...9 months, for a long trek across Europe; I am not responsible for what they do during said 9 months in that car. More to the point, I am powerless to stop them and certainly should not be held to account if they crash it.
Likewise, just because a man has sex with a woman and conceives does not mean there is equal responsibility. She has the final say and the responsibility; not least because it's her body as you love to rightly claim. There's no reason why the man should be held responsible or accountable for what she does with 'her body' or any foetus/foeti within during those 9 months; whether she decides to carry it to term or otherwise, if it is against his wishes. Just as the woman can abort the foetus, keep it, or put it up for adoption, depending on what is for or against her own wishes.