Sex when performed between a husband and wife, for enjoyment or procreation is not wrong.
The idea that sex should only be used for procreation and even so it is still a sin originated in the 14th century, at the same time as the introduction of the term "fornication." FYI this is also when the term "sodomy" (sp?), and a few other like terms originated as well. At the time priest were even permitted to marry and have families, and believe it or not alter-boys were used for the purpose that priests are currently being sued for (remember the Roman-Catholic Church had definate Roman influences in it), but when Pope Something-or-Other came to power he changed Church law to reflect his own disgust with the topic of sex; Priests were no longer allowed to marry, sex begame "taboo" and a sin, the term "sodomy" with the definition of sexual immoralities originated, even the idea that Sodom was destroyed for these sexual practices, instead of the then traditional teaching that Sodom's destruction stemmed from the Sodomites rejection of God's laws and the pride to assert their own authority, got shoved by the way-side to further the anti-sex campain of one pope and his minions.
Premaritial Sex is traditionally a sin, BECAUSE of the origional definition of Adultery. Adultery = sex with anyone to which you are not married. Futhermore, masturbation is commonly concidered a sin due to the incidence rate with which doing so is directly connected to lust. Lust = "dirty" thoughts. According to Christ, even thinking a "dirty" thought about a memeber of the opposite sex is adultery. However, the history of Biblical translation shows that personal biases influence the nature of a translation, and concidering the history of the Church, especially a small number of popes, for manipulating information to suit their causes, much of what we know may be inaccurate, but it may be perfectly accurate too, we do not know.
FYI. The bible was assembled by the Council of Niccea, under commission of Constantine. The 4 gospels are believed to have been choosen for their consistency with each other and that each one directly regards Jesus Christ as God incarnate, this fact was decided upon by a VERY close vote by the members of the council. Historical records suggest that their may be as many as 150 unused gospels, one that may have even been written by Mary the mother, kinda makes you wonder if they exist and what is in them if they do, huh?
There are 15 Hebrew words that were only translated as "love" into English; 17 that translated simply to "death." Tell me how ANY English translation can be truthfully accurate. The idea and the message, The WORD, as it may be, is all that really matters.
Christ is the way, the truth and the light. Keep him in your heart and try your best, that is what God asks of you.
BTW, I am a practicing Roman Catholic, I am 24 and I am a Virgin, 100% by choice, and not always an easy choice either. I would like to be able to say that I am always pure in thought, but that would be a lie. Furthermore, as you may guess, I do not take everything the Church says as word, I have explored the teachings of other Christian Denominations, but at the end of the day I am still Catholic, since many of the cole beliefs are closer to that which I feel underlie the teachings of Christ and the Bible.