Well, actually it does. You can easily find online where it is documented. As for girls you are not allowed to have virginal intercourse with them under the age of 9 although other types of pleasing yourself with their body is acceptable. I'm not sure what it says in details about boys but I'm sure it's similar. The age thing is not a hard fast rule since there is a story about one of the head guys (I forget his name) deciding he wanted a visitor's 4 year old daughter because she was beautiful and they could hear her cries and screams all night. This was considered OK..
The prophet of Islam, Muhammad, set the standard for Muslims in the Qur’an. He married a girl, Aisha, who was just six years old. It says in the Qur’an that Allah sanctioned this for the prophet, and for all who follow Islam. It says in the Qur’an that Allah permitted Muhammad to to consummate the marriage to Aisha when she was nine. Before then, he was allowed to fondle her, rubbing, kissing and sodomy is allowed. A man having intercourse with a girl younger than nine years of age has not committed a crime, but only an infraction, if the girl is not permanently damaged