Born in the province of Groningen, Hekma studied anthropology at the Free University in Amsterdam and completed a thesis on the medicalisation of homosexuality in Holland. Since 1984 he has been a lecturer in gay studies at the university of Amsterdam. His specialisation is sociology and history of (homo)sexuality

In 1975, he joined the radical gay group "The Red Faggots". He co-organized the first gay film festival in Holland in 1976 and a gay cultural festival in 1980. Since 1983 he has organized several internatonal gay and lesbian studies conferences in Amsterdam and Paris. He has co-edited seevral books on the sociology and history of (homo)sexuality.

In his private life, he is a confirmed satinist (one who has fetish for satin), Sadian and book collector.

He now works on an encyclopedia of perversions, on the Dutch poet Jacob Israel de Haan, on discrimination of gays and lesbians in The Netherlands, on sex capitals and on a comparison of gay emancipation after WW II in various Western countries.