((a)) ** Homosexuality and bisexuality** For purposes of the definition of “disability” in section 12102(2)  of this title, homosexuality and bisexuality are not impairments and as such are not disabilities under this chapter.1

((b)) ** Certain conditions** Under this chapter, the term “disability” shall not include—

((1)) transvestism, transsexualism, pedophilia, exhibitionism, voyeurism, gender identity disorders not resulting from physical impairments, or other sexual behavior disorders;

((2)) compulsive gambling, kleptomania, or pyromania; or

((3)) psychoactive substance use disorders resulting from current illegal use of drugs.