Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, Elevation of Privilege (mnemonic for threats to software, used to make threat-modeling scenarios)
Only falling under the general term of transsexual. The DSM1 IV estimates 1 in 30 thousand males are transgendered and 1 in 100 thousand females have identified themselves as having very strong trans feelings. {Definition of Transgender being born one physical sex, but their actual sex is different.
There are a number of theories about why transgender people exist although there is not yet scientific consensus. When you look across cultures, you will find that people have had a wide range of beliefs about gender. Some cultures look at people and see six genders, while others see two.