WASHINGTON  “I spent the summer before college reading Shakespeare and staring out the window and occasionally being a roadie for my friend’s band,” says Eve Tushnet, the celibate, gay, conservative, Catholic writer. That was all good fun, she says upon meeting in Union Station, but she was ready for more, although she knew not what. “I was hoping for something very different in college.”

It is common, this freshman urge for self-invention. The football player tries his hand at poetry; the classical violinist fiddles in a bluegrass band. But Ms. Tushnet  whose parents, Mark Tushnet and Elizabeth Alexander, are a well-known liberal Harvard law professor and a former American Civil Liberties Union lawyer, respectively  did not imagine that she would become a Roman Catholic, nor that 10 years after graduation, her voice, on her blog and in numerous articles, would be one of the most surprising raised against same-sex marriage.

As the hundred or so daily readers of eve-tushnet.blogspot.com, and a larger audience for her magazine writing, know by now, Ms. Tushnet can seem a paradox: fervently Catholic, proudly gay, happily celibate. She does not see herself as disordered; she does not struggle to be straight, but she insists that her religion forbids her a sex life.

“The sacrifices you want to make aren’t always the only sacrifices God wants,” Ms. Tushnet wrote in a 2007 essay for Commonweal. While gay sex should not be criminalized, she said, gay men and lesbians should abstain. They might instead have passionate friendships, or sublimate their urges into other pursuits. “It turns out I happen to be very good at sublimating,” she says, while acknowledging that that is a lot to ask of others.