Green triangles were worn by murderers. A bewildering array of stigmatization. Holocaust research in general is difficult, but for research on homosexuals the problems multiply. First, the data that exist are often unreliable, and primary data are scant and inadequate. Many records were lost or destroyed.
Complete reports are hard to find.
Furthermore, under the Nuremberg Laws in which genocide was defined after the war, the killing of homosexuals was not considered a crime against humanity or a war crime. For all these reasons, it was very difficult to find and interview gay survivors of the Holocaust. Some scholars have also been homophobic on the subject, either overlooking homosexuals or simply dismissing them. In the 1930's, there began in Germany a persecution of male homosexuals that was, like that of Jews, the worst in their respective histories. Lesbians, since they could contine to breed children, presented no practical reproductive problems to the Nazi state.