Nearly two-thirds of secondary school teachers in Wales believe that pupils should learn how to obtain an abortion in sex education lessons.
In an exclusive poll for TES Cymru, 60 per cent of secondary staff in Wales said pupils should be told how to terminate an unplanned pregnancy. The figures were higher still in England, at 69 per cent.
Overall, 59 per cent of English and Welsh teachers, including primary, supported advice on abortion being part of sex education. Support was higher among heads and deputies than other staff, and more men (65 per cent) than women (56 per cent) were in favour.
The survey also reveals that teachers take a strongly liberal line on pupils learning about contraception and discussing homosexuality.
In Wales, guidance on sex and relationships education (SRE) is issued by the Welsh Assembly. It says abortion would usually be covered in a school's SRE policy, but that people have strongly-held views and beliefs, and the religious convictions of parents and pupils should be respected.
It emphasises reducing pregnancy through contraception or abstinence. Wales has a higher rates of teenage pregnancy than England, but lower abortion rates. In 2003, abortions were up 3 per cent to 7,615 - a rate of 13.2 per 1,000 women (16.6 in England).
Ruth Kelly, the Education Secretary in England, is a devout Roman Catholic understood to oppose birth control and abortion. Sex education campaigners are concerned that her private religious views should not lead to changes in government guidance to schools.
A spokeswoman for the Family Planning Association, which advocates compulsory topics for sex education, welcomed teachers' support for providing information about abortion.
"People of all ages find it difficult to know where to go in these circumstances, what to do and who to get help from," she said.
Welsh teachers were almost unanimous in their backing for education about contraception, supported by 97 per cent (98 in England), while 85 per cent (89 in England) also said pupils should be told about the morning after pill.
The FPA spokeswoman said these should form the core of sex and relationships education, but schools were failing to teach them properly in many cases.
She said: "It's about giving young people information and knowledge, but also developing the skills to consider their own attitudes and actions."
Most teachers said they would be happy to tell a pupil that it was ok to be lesbian or gay, with 63 per cent in favour in Wales (75 per cent in England), rising to three-quarters of those aged under 40 in Wales.
Gay rights group Stonewall welcomed the "encouraging" response to what is believed to be the first research on teacher's attitudes to homosexuality.
Asked whether schools should provide confidential advice to girls under 16 who become pregnant, 44 per cent of Welsh teachers agreed, while 49 per cent disagreed. But four out of five believed parents should be told if a girl decided to have an abortion.
The phone survey, of 200 Welsh and 500 English teachers, was carried out by FDS International.