Having a large family may be genetic because men whose ancestors had more children ‘are more fertile’
- For every offspring in the family subject’s sperm count increased by 1.8 million
- Struggles to conceive also inherited, as smaller families continued generations
- A group of 2,182 men from Utah, U.S, were studied tracing their families to 1935
Men from larger families tend to have better quality sperm, a study has found.
Researchers at the University of Utah discovered that men whose ancestors had more children have a higher rate of healthy moving sperm.
Comparing the men’s sperm with the number of children in nine generations of their predecessors found that for every extra child in the family’s history the subject’s sperm count increased by 1.8million.
Struggles to conceive could also be inherited, as smaller families appeared to continue down the line for generations.
Researchers at the University of Utah, U.S, discovered that men whose ancestors had more children have a higher rate of healthy moving sperm (stock image)
Speaking at the American Society for Reproductive Medicine’s annual meeting in Philadelphia the report’s authors said: ‘This is one of the first studies examining the relationship between intergenerational family size and sperm count as a marker of male factor infertility.
‘We found a significant association between sperm count as markers of male factor infertility and family size, suggesting that lower sperm count is related to smaller intergenerational family size.’
A group of 2,182 men were studied by the researchers, comparing sperm samples to the Utah population database and tracing their families to 1935 and earlier.
They found men from historically larger families tended to have almost two million more healthy sperm.
A normal sperm count ranges from between 15million and 200million per millilitre of semen.
Any less than 15million is considered to be a low sperm count and may affect the man’s fertility.
Speaking to The Telegraph Dr Peter Schlegel, president of the American Reproductive Society said: ‘This study shows us a clear picture of how male fertility may be inherited.
A group of 2,182 men were studied by the researchers. 3D illustration of sperm cells (stock image)
‘Though it would seem paradoxical that male genes can influence when a woman becomes a mother for the first time and how many children she may have, although they conceded social factors were increasingly playing a larger role in family size and timing.’
Earlier this year Danish researchers found that boys have fewer sperm if their fathers smoked cigarettes before they were conceived – after analysing semen samples from almost 800 teenagers.
They discovered those whose fathers smoked daily before they were conceived had sperm concentrations around eight per cent lower.