CAMBRIDGE, Massachusetts: Some time between the founding of a student-run porn magazine and the day the campus health centre advertised ``Free Lube'', Harvard University seniors Sarah Kinsella and Justin Murray decided to fight back against what they see as too much mindless sex at the elite university.

 They founded a student group called True Love Revolution to promote abstinence on campus. The group, created earlier this school year, has more than 90 members on its Facebook.com page and drew about half that many to an ice-cream social.

Harvard treats sex -- or ``hooking up'' -- so casually that ``sometimes I wonder if sex is even a remotely serious thing'', said Ms Kinsella, who is dating Mr Murray.

 Other schools around the country have small groups devoted to abstinence. On most campuses, they are religious organisations.

 Princeton and the Massachusetts Institute of Technology have Anscombe Societies, secular organisations named after an English philosopher and Roman Catholic. True Love Revolution is also secular.

 Some feminists, in particular, have criticised True Love Revolution's message.

 Harvard student Rebecca Singh said she was offended by a valentine the group sent to the dormitory mailboxes of all freshmen. It read: ``Why wait? Because you're worth it.''

 ``I think they thought that we might not be `ruined' yet,'' Ms Singh said. ``It's a symptom of that culture we have that values a woman on her purity. It's a relic.''

 Others on campus have mocked the group. Mr Murray said his friends took pleasure in loudly and graphically discussing their sex lives just to taunt him.

 ``On campus there is such a strong attitude of pluralism and acceptance, but then it doesn't extend to this,'' Ms Kinsella said.

 In the student paper The Harvard Crimson, columnist Jessica Coggins praised the group's low-key approach and scolded Harvard students for their ``laughter at the virgin''.