The fact of the matter is that child support, paternity, family and divorce are all nuanced situations, and that our current system is hopelessly inept at solving the various problems that arise. Men are tricked into impregnating women every day, and I'm sure that there are men who intentionally get women pregnant against their will also, (other than rape, obviously) forcing her to make an awful choice.
There was a time when I would have agreed wholeheartedly that the child support system (as it stood in the courts) was rigged in favor of women. After decades of men walking away from their responsibilities, this was even expected. The view I now take is that in many cases, the courts are biased against the non-custodial parent. This varies by state, as some are better at child support enforcement than others, but none I know of are ideal. Some like Indiana, are among the worst.
Personally, I wouldn't use the argument about it being the man's or woman's choice to have sex. There are other, more persuasive arguments to use to convince others of the importance of taking responsibility for any children. I know I wouldn't use this argument on a pro-fetus side of an argument (not that I am, I'm pro-choice anyway) and so it seems contradictory to me to use it against a man to encourage him to take responsibility. Many of us on the pro-choice side realize that many teenagers are going to end up having sex, whether taught safe sex methods or not, so I would expect the same from most women and men as well. They may in general be more responsible sexually, but then again they may not be. They may also be generally very responsible people, but are overcome in the heat of the moment when it comes to sexual activity. There are many factors that go into a choice to have sex, and many that are ignored as well. I haven't looked into the actual statistics, but my hunch is that most people who are sexually active have made the mistake of under utilizing or not utilizing some sort of birth control or protection from STD's. Have you or anyone you've ever known made this mistake? Imagine how your life or theirs might be completely different if they didn't get "lucky" and have no consequences from their slip up.
There are just so many ways to be dishonest - whether men or women in these situations, and almost all of it comes down to one version of events vs. another. There's got to be a better way than we currently have, but I'm not sure what that could be.