Because they don't think past their desire to get off.

because they are idiots.

Because they are making BAD decisions by using the wrong head.

Because any guy can get a woman pregnant, but it takes a real man to take the responsibility for his actions and become a father and a husband.

Generally those guys don't intentionally get the girls pregnant. I know, I might be blasted for it, but why did the girls sleep with the guys without knowing they wanted to be husbands, "much less fathers". Members of both genders know going into it that they might create a child with the act of sex. And despite the implications of this question, the vast majority of guys, nearly all of them, don't go around misleading women into thinking they want to marry them and father their children just to get into their pants. Those are only the few, sick bastards, probably invariably psychopaths or at least possessed of psychopathic tendencies. I've had sex with girls and had condom breaks, and 2 times it was an issue (I'll explain that in a moment). Each time I was very supportive, offered to help the girls take care of it, with money and discretion and my time getting the morning after pill, or, worst comes to worst (never came to it thankfully), an abortion if that's what they wanted. I never want to be a father. I don't want children. Kudos to those that to, but I'm not one of them. Maybe it's that my family growing up was horrible and I was "raised" to distrust marriage and want to avoid these sorts of responsibilities or commitments, or maybe it's that I already have all the responsibility I need for a lifetime raising and supporting my schizophrenic brother as his sole caregiver in the absence of either of his parents. Maybe I just know not everyone, despite society's pressures, is cut out for parenthood or marriage. I know I'm not. So I had a vasectomy, two years ago, at 25. I will never get a girl pregnant. I chose to be responsible, AND to have casual sex without consequences (except maybe disease, but it's not like I'm a promiscuous man-slut!). The three other times I've had condom breaks, I've gently told the girls, and in one case proved it, that I was surgically infertile. And all was well with the world. I think choosing to be childfree was the best choice I ever made, and it's as beautiful, or moreso, a choice as having a child. Many "fertile" breeders aren't ever going to be truly ready to be parents. Most force it when they have no choice, and it shows. Equally, many are not ready, nor ever will be, for monogamy, and it shows in the divorce rate and in their actions pre-marriage. There is usually no one at fault - neither the man nor the woman. Only if one of them is deliberately misleading the other (or themselves!) is there a villain. It's easy to think in terms of good and evil, black and white, but life isn't really composed of those things.

Because the brain and the genitalia aren't necessarily connected.

Umm.. guys don't "get" girls pregnant. men and women make foolish mistakes, including NOT using contraceptives, and together, become pregnant. If a woman "gets pregnant" she's just as guilty as the man. If you're old enough to have sex, but you're not ready to have a baby, you damn well better be taking the pill AND using a condom... and you better not say "oh, just this once" - cause you'll get pregnant. Guys, same thing, unless you're ready to be a father and/or contract diseases, some which are fatal and more incurable, you'd DAMN WELL better be using a rubber! If you don't, you'll end up liable for child support, whether you want a kid or not... There is NO EXCUSE.

The same reason girls let them lie to them & not use any form of birth control. We as females are responsible for what happens to our bodies & I know from experience in that once split second decsion can make you a mom for the rest of your life. Some girls think its a way to keep that man for life, but they don't realize they won't be there. Some young guys turn out to be great lil daddies others just keep spitting them out like trophies & never taking care of them. Thats what we females need to think about before we sleep with them, ask them to see what their ideas are with kids, if they are lazy & shallow don't bother wasting your precious time on them because you know they won't make a good daddy for your baby. Use that energy for a real man, one who is responsible with morals & values that way if a slip up would happen you know they would help if you needed it.

It's not just down to the guy you know - it takes two. On the flip side, there are lots of girls who want the baby and nothing more to do with father. Things to remember are: Guys: Never, ever, take her word for it that she is using contraception - take responsibility for yourself whatever she says. If you have unprotected sex with a girl and she falls pregnant, it is your fault as much as hers. Girls: If you are girl, don't have unprotected sex and then get pregnant through your own lack of responsibility. If you do then you don't have the right to whine and bleat when the guy in question says he does not want a child - he has as much right as you to say 'I don't want a baby'. Both of you: Do not have unprotected sex - get some contraception before you get together. There is no excuse in 2007, it is no good moaning about available methods because you don't like them or somebody told you they caused you to get fat (the pill). To allow yourselves to create a human life when it is not wanted, is selfish, immature and shows a severe lack of responsibility. You do not have the right to just make babies because you can't be bothered not to. Will it wreck your life if you do - well not completely but it will make the rest of it harder and more problematic that it should be. The person who will pay for your selfish, childish choices is ultimately, the kid. The second they are born, they will automatically be at a disadvantage. A child (where possible) should have a Mum and Dad who are in a stable & loving relationship. You should be financially secure, have somewhere to live, one or both of you must be working full-time, you must be able to provide food and pay the electricity bill on time. The child must be wanted by both parents and not be a mistake you were stupid enough to make because you thought you knew it all. If you want to indulge in adult activities, then you should be an adult when you do, not a selfish, inexperienced child who has their brain up their ass. And that goes for both of you.

Their only morals are found between their legs and in lustful satisfaction. Girls need to understand that boys are hormonal 100% of the time and not just on a monthly cycle. Beware of them!

Why would a girl put themselves in a situation where they could get pregnant by a guy who doesn't want to be a husband or father?

From the point of view of the guy..why do some girls "forget" to take birth control pills and get pregnant hoping their guy will "do the right thing" and marry them? Girls do not have to get pregnant unless they want to...guys may be depending upon the girl to be honest and sometimes the girl wants marriage so much she is willing to entrap the guy. That is not fair. If the girl faithfully takes the pill and still gets pregnant (I guess they are not 100% effective) then "the problem" is something that both parties should deal with together. But I do not believe in entrapment of any kind..that is cheating and I don't think cheating ever brings you anything of value.