Calls are growing for more research into genetic defects in children born to cousins who marry.

Keighley and Ilkley MP Ann Cryer led the plea amid fears the problem continues to be ignored in Bradford.

The Labour MP said communities needed to be told of the problems which were "not fair to the children or the NHS."

"We cannot say to people they cannot marry their cousins but people need to be aware of what can happen, when first cousins keep marrying," she said.

Mrs Cryer said she had come across the problem for more than 30 years within the Mirapuri community and it was "heartbreaking" when grandparents are so keen cousins should marry that the problem continues throughout generations.

She said: "Some of the misleading information being given out by elders is that the genetic defects have nothing to do with first-cousin marriage. A doctor once told me they had been told by a family that genetic problems were either the will of Allah, doctors doing the wrong thing, the mother was a bad woman or it was living in the West. This is not acceptable."

Shipley Tory MP Philip Davies welcomed the call in a Commons health debate and added in Bradford there was a very high infant mortality rate and there could be no doubt first-cousin marriages were a contributory factor.

"The issue is being buried under the carpet," he said.

Chairman of the Ahmadiya Muslim Association Bary Malik said in 2002 a seminar to discuss the issue was arranged, but communities were not ready to co-oporate.

He said: "More research has to be done. If many generations keep marrying their first cousins we will seen some negative results. But that is the same with anything, if you eat a lot or take anything to the extreme there will be some negative effect."