Tory MP David Jones says same-sex couples cannot provide 'warm and safe environment for the upbringing of children'

Conservative anti-gay prejudice was under scrutiny again on Friday after the Welsh secretary, David Jones, was forced to backtrack on an assertion that gay couples "clearly" cannot provide a "warm and safe environment" in which to raise children.

His comments, made on a Welsh TV programme, came as the Tory party struggles to maintain unity following the vote 10 days ago on the government's plans to introduce same-sex marriage.

Jones, one of two cabinet ministers to vote against gay marriage, told ITV Wales's Face to Face programme: "I regard marriage as an institution that has developed over many centuries, essentially for the provision of a warm and safe environment for the upbringing of children, which is clearly something that two same-sex partners can't do.

"Which is not to say that I'm in any sense opposed to stable and committed same-sex partnerships."

He did not believe he was homophobic, insisting he had "people in my life who are important to me who are gay".

As criticism poured down on him – the shadow Welsh secretary, Owen Smith said the "profoundly offensive" comments proved that the "nasty party" was still alive – Jones issued a statement seeking to clarify his remarks and expressing outrage that his remarks were misinterpreted.

He said: "I was asked on the Face to Face programme why I voted against the same-sex marriage proposals. I replied that I had done so on the basis that I took the view that marriage is an institution that has developed over the centuries so as to provide a safe and warm environment for the upbringing of children.

"I made the point of stressing that I was fully supportive of committed same-sex relationships. I also strongly approve of civil partnerships.

"I did not say in the interview that same-sex partners should not adopt children and that is not my view.

"I simply sought to point out that, since same-sex partners could not biologically procreate children, the institution of marriage was one that, in my opinion, should be reserved to opposite-sex partners."

Gay people were given the legal right to adopt children under the Adoption and Childen Act 2002, implemented in 2006 following legal challenges.

Jones's clarification implies that he believes the chief purpose of marriage is procreation, and therefore gay people should be debarred, apparently ignoring the many married hetrosexual couples who do not have children.

The prime minister's spokesperson said: "The prime minister believes gay families can provide warm and safe environment for raising children." Downing Street stressed that David Cameron regarded same-sex marriage, as well as gay adoption, as conscience issues.

Jones's comments led to a torrent of critcism and some scepticism of his claim that they were misinterpreted.

Chris Bryant, the shadow immigration minister and Labour MP for Rhondda, described the remarks as hurtful and called on Jones to apologise. "The secretary of state for Wales is ably demonstrating how out of touch the Conservative party still are when it comes to modern British life," he said.

"Many gay couples are parents and provide loving homes for their children. Surely if his argument is about strengthening families, then the logical conclusion is to allow same-sex parents to marry?"

Ben Summerskill, chief executive of the lesbian, gay and bisexual charity Stonewall, said Jones's words showed the breadth of the gulf between some Tories and their leader.

"I'm sure it will be a reminder to the prime minister that he's made a lot of progress in modernising the Conservative party but there's still rather a lot of work to do. It's all a little bit tragic that he can think this sort of guff will not be regarded as odd – and particularly by young people.

"It's interesting that the issue of marriage should have smoked out an expression of prejudice that we rather thought had gone out with Section 28.

"There is now hard evidence that children who grow up with two lesbian or gay parents do not differ in any way in terms of their social or intellectual or sexual development from children who grow up with heterosexual parents, so it's not even a prejudice that has some basis in evidence."

Carol Homden, the chief executive of Coram children's charity, said: "Coram has worked with many gay adopters in our 40 years as a voluntary adoption agency who have made a life-changing difference to children in need of a permanent family. It is against the law to refuse to assess people on the basis of their sexuality."

Originally a solicitor, trained in London, but working in Wales, the Welsh-speaking MP for Clwyd West was appointed to the cabinet in the September 2012 reshuffle after spells in the Welsh Assembly, as a backbench MP and then shadow and junior minister.