My Boyfriend Won't Sleep with Me.

I recently got an e-mail from a woman in her 20s saying, "My boyfriend won't have sex with me. Can you tell me what might be going on?"

So for those of you whose boyfriends won't sleep with you, here are some reasons men are cold in the sack.

He believes his tool might be too small

• Men are obsessed with their private parts and they can be riddled with an inferiority complex about its size quite easily.

  Maybe he has seen the sizes of other men's privates in the locker room and felt he didn't measure up, or was ridiculed about its size by a former girlfriend. If this is the case with him, he might need professional help before he will let you see him naked.

He can't keep it up

• Erectile dysfunction is normally a problem associated with men of an older age, but there are also many men in their 20s and 30s who have who cannot perform.

  And if he isn't aware that this problem can occur at any age in men, he might be especially distraught. Men in this situation need to speak to a medical doctor to see if anything can be done.

He might be gay

• There are men in relationships with women who are hiding their real sexual orientation. Gay men might make great partners for women in intellectual, emotional, or spiritual ways, but the physical component is simply not meant to be.

  Some gay men lead double lives and are sexually active with both men and women (in which case you might never find out he's gay), others simply will not have sex with a woman. If you suspect he might be gay, observe if he looks at other men or checks them out.

He believes in waiting until marriage

• Some men are still old-fashioned (which is a good thing) because they were either raised to believe in waiting, or because they have religious beliefs that deem waiting is respectful to God.

  While you might be thinking, "My boyfriend won't have sex with me because he isn't attracted to me," the reality simply might be that his moral code won't let him do it.

  You will usually know if believes in waiting until marriage by understanding whether he is religious in general. Does he talk about praying? Does he mention God often? Unless he tells you outright that he wants to wait, those are some good clues.

He is very nervous

• We are raised in American society to think that men are always sexually aggressive. This is not so. Some men wait for women to make all the moves before getting into the action themselves.

  You can find out of this is the case with him by being very obvious about what you want -- put your hand over his crotch and caress it. If it is purely about nerves and he is a heterosexual guy, then he should respond.

Would you still stay with him?

Some of the reasons he might not be sleeping with you, such as the nervousness or waiting until marriage will eventually resolve themselves. Others, such as the possibility of him being gay and obsession over size, might not.

In any case, you have to figure out for yourself if the man you are with is worth staying with through any of these situations. Are you only into your guy because you are sexually attracted to him, or are you interested in the long-haul no matter the outcome?

Some of these situations might not be conducive to a healthy relationship. You will have to decide for yourself what you are comfortable with.