Brongersma was primarily known for his publications and his advocacy of more lax morality legislation, a subject in which he was keenly interested. Because of his expertise, he played a major role in 1971 as a member of the Senate in abolishing Article 248bis of the Dutch Criminal Code, the same article on the basis of which he had been convicted in 1950. The age of consent for homosexual contacts was then lowered from 21 to 16 (the same as for heterosexual contacts). He advocated lowering the age of consent even further.