The WTS view on sex is fairly puritanical and fundamentalist as far as I'm concerned.
Since God(or whoever wrote the Bible) didn't make a list of things that displease him regarding sexual practices between husband and wife, the WTS has taken it upon themselves to create a pharisee-like set of rules to make sure everyone keeps "clean" before Jehovah. But they demonize sex so much that people who grow up in the "truth" can have issues when it comes to enjoying sex even in a legal marriage union. While abstainance from sex before marriage may be a moral issue for many people, I'm sure they don't limit themselves to the set of rules that JWs are forced to obey.
If you're single: no riding in the car alone with the opposite sex. No sitting next to each other(interested boy/girl) at the hall/convention unless marriage is the ultimiate goal. No recreational dating. No dating without a chaperone. Even group dates have to be careful to not let two people get alone for any length of time. No "heavy petting" or making out. Holding hands and kissing have been counseled against by some dopey elders. This kind of shit can fuck you up when you're finally interested in getting married. Hell, if you followed all those rules to the tee, you'd be afraid to kiss your bride at the wedding lest you get counseled for giving her the tongue.
Is it no wonder that young JWs who have not gotten past the bloom of youth are so horny that they marry the first person who holds their hand? They bottle everything up and sooner or later it's got to come out. According to the WTS all you gotta do is read your bible and all's well. But different people have different sex drives. Some people are more sexual and need a sexual outlet. The WT way of dealing with sexuality just creates problems for such ones. If younger ones could mature into the age of being ready to marry instead of follwing the same lameass rules as a 12 year old, maybe they could get past that getting married at 18 or 19. Almost every JW marriage that I can think of that started at 18 or 19 has ended in divorce. Because they weren't really in love. They were horny and the only way to get off was to get married.