DANISH men have been walking around with temperature sensors in their underpants.
Sperm are known to fare better at cooler temperatures, and warmer testicles have been linked to infertility. So Niels Henrik Hjollund of Aarhus University Hospital in Denmark and his colleagues measured the scrotal temperature of 48 men, including identical and non-identical twins, and non-twin brothers. They found that it varied least between identical twins, suggesting that genes are involved.
This is the first evidence that infertility could be due to genetic factors other than those involved in sperm manufacture itself, say the researchers in Human Reproduction (vol 17,…
