Diversity related to gender identity and sexual orientation is about two different things (DILCRAH, 2019); both can be discriminating. Being "trans" is not a fantasy; trans-identity is imposed on the individual. The World Health Organization (WHO) removed it from "mental illness" in 2019. Researchers have shown that it is not pathological. When it comes to sexuality, there is no such a thing as "normal". Sexual orientation is a major source of discrimination because it is an intimate and very personal subject which requires knowledge in  psychology, or psychoanalysis. One can easily fall into caricature and clichés, such as the stereotype of "transvestites" which have often been a source of mockery, which are the first step for more serious violence. Definitions related to trans-identity and sexual orientation are important to know in explaining why homosexuality is considered a "difficult" issue in education.The strategies and public policies carried out to fight against homophobia have adapted to a particular form of discrimination - in terms of gender identity or sexual orientation, it consists of forcing invisibility, oppressing transgender people or homosexuals by bullying or harassment, or by "ordinary" and systematic mockery against people qualified as "effeminate" (for men) or "masculine" (for women). "Institutional" forms of discrimination have also been successfully combated, such as the end of the criminalization of homosexuality in France in 1982 or the end of the characterization by medical authorities of "mental illness". The fight for equality of opportunity and treatment began in France in 1977; it materialized with the adoption of the PACS (in 1999) and then marriage for all (in 2013). Thanks to these social and legal achievements, mentalities have evolved, and bullying and harassment are now clearly identified as discriminatory and liable to prosecution. In the world, the “gay pride” movement has helped change mentalities; it started in America in 1969, with the fight for civil rights. It was the start of recognition in Europe and around the world (ILGA Europe annual report). It is also important to provide examples of “role models” for example in sport.The case studies are important to understand the evolution of mentalities - the strategy of the American army which went from a prohibition (discrimination) to a benevolent neutrality ("Don't ask, don't tell") and finally, a real recognition of this diversity; or the European MigrAID project which offers training to combat all forms of discrimination in SMEs and social partners.