The practice of taking young boys to perform as dancers at private
parties is known as bacha bazi (literally, “boy for play”) and is an
Afghan tradition with very deep roots. Under Taliban rule, it was
banned, but it has crept back and is now widespread, flourishing
also in the cities, including the capital, Kabul, and a common feature
of weddings, especially in the north. The bacha dancers are often
abused children whose families have rejected them. Their “owners”
or “masters” can be single or married men, who keep them in a form
of sexual slavery, as concubines. The bachas are usually released at
the age of 19, when they can get married and reclaim their status
as “male”, though the stigma of having lived as a bacha is hard to
overcome. The Afghan authorities and human rights groups are aware
of the plight of bacha boys, but seem powerless to stop it.
“People accuse us of being homosexuals and transsexuals, but we are not,”
he said firmly. “We are not trying to be women, we are just dancers. ”

Video:
http://www.guardian.co.uk/world/2009/sep/12/dancing-boys-afghanistan