50% rule

~noun

Entry: a common belief that 50% of all transsexuals die before the age of 30, usually by suicide. The number is probably greatly exaggerated today. This is a depressing term to start off a glossary. On the bright side, sexual reassignment procedures have a very high success rate if proper protocols are followed. Many post-operative transsexuals are quite pleased with their body modifications.

@ Milton-Kindersley Advanced Dictionary