England's largest group opposed to gay marriage is urging parents to withdraw their children from sex education classes.

The UK government approved a marriage law earlier this year and the first weddings of gay and lesbian couples are expected to begin next summer.

The Coalition for Marriage, which vociferously opposed the legislation, released a guide for parents and teachers titled Respecting Beliefs About Marriage.

The guide was introduced in a nearly two-minute Marriage Minutes video.

“It [the guide] will help schools understand their legal duties to handle this issue in a balanced way and it will help schools respect the various beliefs of staff, parents and pupils,” host Dr. Sharon James says in the video. “Many of them sincerely believe that marriage is the union between one man and one woman. The government has made it clear that these people should not be bullied, sidelined or disadvantaged for holding that belief. And this guide will clarify the legal rights of both teachers and parents.”

However, the guide argues that any discussion about gay couples marrying is a form of sex education and informs parents that they have a right to withdraw from such classes.

“[D]epending on the context and level of detail covered, a parent could argue that a lesson or scheme of work which intentionally covered marriage or same-sex marriage constitutes sex education. Whether or not such teaching was called sex education would not prevent such a claim being made with an attendant request for a right of withdrawal,” the guide states on page 17.