Magical Mrs. Mistoffelees
You didn't answer my question, but okay. Because you wish to have a child, and you are not taking the risk of disease proper responsibility behind it. Meaning that if you catch a disease, you would have to pay for the medical bills, not your parents.
Now would you kindly answer the question.
I didn't answer said question because it actually didn't look like it was directed at me. You did answer it yourself, but whatever.
But first of all, you're assuming that the only reason to have sex is to have children? Yeah right. If "adults" only have sex to procreate, explain why contraceptives exist, Explain why the majority of abortions are done by adult women who have used protection and it failed? People have sex for other reasons then procreation even as they are adults. Heck, people who are infertile due to genetics, accidents, or simply old age keep having sex even though they cannot have kids anymore.
Not to mention, even if you are underage, STDs don't pop out of nowhere. It's called getting tested before having sex.
Now as for your question, first of all ->
http://marriage.about.com/cs/sex/a/sexfrequency.htm
Second, yeah because it feels good, because a person wants to share a bond with another, because someone is in love with the other, do you want other clichéd reasons?
Reasons to have sex are personal and change from person to person. If you feel like having a kid is the only reason, then good for you, that's your opinion. But hey, for some people that's a terrible reason, just as "'cause it feels good" seems to be a terrible reason in your opinion.