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The Human Fertilisation and Embryology Bill would allow the selection of embryos that are a tissue match for a sick older brother or sister.
But Tory David Burrowes said it was wrong to create a child for the benefit of another, regardless of "the need".
His bid to ban tissue typing outright was voted down by 342 votes to 163.
A further amendment by shadow health secretary Andrew Lansley to only allow tissue typing and sex selection in cases where the other sibling is suffering a life threatening illness was defeated by 318 votes to 149.
Updating laws
The debate followed a vote by MPs to back moves to create hybrid human-animal embryos.
A bid by Conservative ex-minister Edward Leigh to outlaw the measure was defeated by 336 votes to 176 - a government majority of 160.
They are the first in a series of critical free votes on emotive issues in committee stage debate of the Human Fertilisation and Embryology Bill, aimed at updating laws from 1990 in line with scientific advances.
In the "saviour sibling" debate, Mr Burrowes...
