The genes that decide what age a woman gives birth

SCIENTISTS have discovered genes that predict how likely a women is to give birth.

Researchers found that certain gene variations made a woman nearly 10 per cent more likely to have a child than one who did not have them.

Some ensure a woman remains fertile for longer by delaying menopause, allowing her a longer period in which to have a baby.

The discovery could lead to the creation of a test that could show a woman if she is ‘safe to wait’. It comes as increasing numbers of women are delaying motherhood due to work commitments. And the researchers added that ‘an improved understanding of the function of these genes may provide new insights for infertility treatments’.

By examining variations in 12 areas of DNA linked to the age we have our first child and the total number of children we will have, the scientists found 24 genes likely to be responsi- ble for effects on reproductive behaviour. Until now reproductive behaviour was thought to be mainly linked to personal choices or social and environmental factors.

But the research by more than 250 scientists worldwide showed genetics had an influence on the first age of having sex, the age at which a mother would have their first child and the age of menopause.

The study, published in journal Nature Genetics, pooled data from 238,064 people for age at first birth and almost 330,000 for number of children. Statistical studies showed women with a certain gene variation were almost 10 per cent more likely to remain fertile and have a child than women who did not.

Lead author Professor Melinda Mills, of Oxford University, said: ‘For the first time we now know where to find the DNA areas linked to reproductive behaviour.

‘For example we found women with DNA variants for postponing parenthood also have bits of DNA code associated with later onset of menstruation and later menopause.’