Reproductively, for one: They can choose to have intercourse or not. If they have intercourse, they can choose to use birth control or not. Same as with men.
But women have extra choices that men don't have, aren't afforded: If a woman has intercourse and gets pregnant, she can give birth or abort it -- the man has no say. A good man cannot make a woman carry a pregnancy that she doesn't want and then allow him to raise that child . . if she wants it aborted, it is aborted. If she gives birth, she can keep the baby or put it up for adoption. If she keeps the baby, she has every right to go after the alleged father for child support (if she receives any sort of public support, then the choice isn't hers -- the State will go after the man). And, while men sometimes obtain custody and the women pay support, that doesn't happen near as much as the reverse -- especially for young children, as courts assume that children need their mothers more than they need their fathers. If the mother can be shown to be unfit, then the father could gain custody, but again that is not the typical outcome.
If she gives the baby to adoption, the alleged father has a small window (in some states, just 30 days) to register on a paternity registry or have all parental rights severed forever. This is true even if the sex that resulted in pregnancy was a brief tryst and he might not know the woman became pregnant, or he might have moved from the area since then. It doesn't matter -- all the law requires (per a seminar I attended on the subject) is a brief listing in a newspaper ("If you think you might have fathered a child, contact . . .") and if the father doesn't see it or know about it, his rights can be terminated forever.
Speaking of "alleged father", how many men ASSUMED, because their dear partner told them so, that a baby is really from him? Every woman (barring some hospital mix-up) knows the baby is hers, but the man wouldn't unless he requests a paternity test. If the couple is married, what husband wants to essentially accuse his wife of cheating by asking for a paternity test? Very few. So, we men rely upon the truthfulness of a woman (and, yes, women are human too and they do lie . . often very well) to acquire the facts. That is, until there is reason to need to know the bio link between father and child (such as, one of them needs a transplant or other procedure, or if a divorcing man latter suspects his wife's infidelity) and the truth comes out. Even then, courts have maintained the child support order for a man that finds out, years later, that the children he assumed were his and that he helped support and raise were the result of his wife's infidelity. His emotional hurt gets compounded by financial damage. A double whammy for him.
Personally, I think a paternity test should be a routine part of the blood testing already done when a child is born. The child deserves to know the truth, and so does the father. If a man doesn't have to request the test, but could decline to know the result, then he would have no one but himself to blame for not knowing if the child is really his. If the child is not his, better for all concerned that the truth be known up front and the couple can then decide to stay together or part based upon facts, not assumptions. But, we are no where near the point of requiring such testing. So, men continue to hope and assume.
As the mother of two sons, I would expect that you want the best for them, as I do my two sons. Knowing the truths I described above, and wanting to give good advise, what do/should you tell them? "Scott and Tommy, I have something to tell you. I hope with all my heart that you will find love and have your own families. But, I also want you to know the realities. When it comes to sex and having children, you have two choices: To have intercourse or not, and to use your own protection or not. After that, most of the decisions are up to the girl. She has the say, not you. Your children are more hers than yours. Don't expect that you will have kids if she doesn't want them or you and her do not stay together. The kids go with her, and you will pay for them. I don't want you to live an unhappy life or think that true love is not possible, but I do want you to know the truth about these things so that you can live your life with eyes open."
I never had that conversation with my sons; unfortunately, I didn't have to. They saw first-hand what I went through and have since told me that they never want something like that to happen to them. I told them I would like to be a grandfather one day. My elder son says he never wants children. The younger son, who is gay, told me he hopes to have children one day, but how he will do that he isn't sure. His babies need to come from some woman, so again he faces the prospect that the women can change her mind at any time and he could still end up paying but not having the children with him. While I was as proud as any Dad to have sons, I think I would worry less if they were my daughters now.
My parting point: You, I, any responsible parent of boys, wants their sons to be good, principled, contributing members of society. But where is the reward for being that, for them? If the outcome for being a quality man is MORE punishments than if one were a low-life man, then what reward is there for being a good man, other than inner satisfaction (which, believe me, fades fast in difficult circumstances)? What do we do, when even a lot of MEN refuse to see the unjustness of it all? How do we get MEN to abandon the fear of being perceived as weak, as bested by a woman, as a victim, as someone who cannot handle life's hurdles? We see what we do -- change nothing. Women banded together to change things for the better for themselves, but men stubbornly refuse to do the same.