Conservative opponent of marriage equality David Davies has said his concerns focus around sex education and how children might be taught the mechanics of gay sex and that this might encourage them to have gay sex.

Welsh Conservative MP David Davies, who last month suggested most parents would prefer their children “not to be gay”, and then dismissed accusations that he is a homophobe by reminding people that he beat a gay man in a boxing match has now gone on to explain in more detail why he is concerned about same-sex marriage.

In an interview with Saturday’s Guardian the MP for Monmouth in South Wales said: “This is where it gets sensitive, but I’ve got three kids, and I know a lot of people with children have got this concern. I hate to say this, I hate to say this, and I don’t want it to cause outrage or offence … ”

“But I suppose, at a certain level, I see heterosexual sex as being – and it’s probably the wrong word to use – but the norm. I think it’s reasonable to say that the vast majority of people are not gay.”

“I just worry if children are going to be taught that [heterosexuality] isn’t necessarily the norm, and that you can carry on doing all sorts of other things, are we going to have a situation where the teacher’s saying, ‘Right, this is straight sex, this is gay sex, feel free to choose, it’s perfectly normal to want to do both. And you know, why not try both out?’ I mean, are we going to have that?

“Can I say something else as well?” he he added. “It may or may not be relevant.” Mr Davies then explained to the Guardian journalist Decca Aitkenhead that a friend at school announced that he was gay aged 16. Before adding that years later “it turned out the guy had got engaged. To a woman! And he absolutely didn’t want to talk about what had gone on between the age of 16 and 19.

“He’d started coming down to the pub at 16 with, you know, splits in his jeans, and started buying Erasure albums, and all the rest of it – and three years later he’s suddenly horrified by the whole thing!

“I suppose what I’m trying to say, in a very clumsy way, which will again probably cause offence, is that some people might be going through a bit of a funny phase between the age of 15 and 20 when they’re not sure. And I’m not absolutely convinced it’s a good idea to be changing sex education in school to try and say to people, ‘Feel free to go out and experiment and do this, that and the other.'”

When the journalist asked him if he would have been tempted to experiment with gay sex if he’d have been taught about homosexuality aged 10, the MP reportedly jumped out of his seat and said: “I reckon in my case, almost certainly not.”

Asked if he wouldn’t then what is the problem with children being taught about homosexuality, he explained: “You see, it’s not so much telling them it happens. It’s explaining in a certain amount of detail how it happens.”

“If you’re going to explain the facts of life you’ve got to explain at some point, penis, vagina, they go together, this is how children are made. Well, do you also have to start explaining in similar detail how gay sex is carried out?”

When Ms Aitkenhead asked him if he could give a reason why more people having gay sex as a result of being taught about homosexuality would be a bad thing, he answered: “No, I don’t think I can, to be honest. I don’t think I can explain it. I can see immediately, if I did, that it would cause offence to some people – and that’s wrong, isn’t it? But I’m not even sure that I can answer your question very well, anyway. I can only say I have a slight sense of unease.”

Partially retracting his now infamous remarks claiming that most parents would prefer their children not to be gay, he said: “If one of my children were gay I don’t think it would make any difference to the way I felt about them at all. I would want them to be happy and contented.”

The root of the concerns that Mr Davies expresses is that marriage is taught about in the national curriculum in state schools. The Government has said that faith schools in particular will be able to describe their belief that marriage is between a man and a woman, while acknowledging that same-sex couples can be married as well.