Having sex every day improves sperm quality and could boost the chances of getting pregnant, research suggests.
In a study of men with fertility problems, daily ejaculation for a week cut the amount of DNA damage seen in sperm samples.
Speaking at a fertility conference, the Australian researcher said general advice for couples had been to have sex every two or three days.
Early results from the trial had already shown promising results.
But 118 men have now been tested and the benefits for sperm have become clearer.
Dr David Greening, from Sydney IVF, told delegates at the European Society for Human Reproduction and Embryology meeting that eight in ten men taking part showed a 12% drop in sperm DNA damage after the seven days.
Although there was a big drop in sperm numbers from 180 million to 70 million over the week, men were still within the normal “fertile” range.
Sperm also became more active over the seven days with a small rise in motility, he added.
The theory is the longer sperm hang around in the testes the more likely they are to accumulate DNA damage and the warm environment could also make them more sluggish after a while.
Sperm come under attack by free radicals – small reactive molecules which can damage DNA and cause cell death – in the tube that stores and carries sperm away from the testes.
Further work is needed to work out if daily sex for men without fertility problems has the same benefits but Dr Greening believes it is likely to be the case.
He warns that having daily sex for too long – say a fortnight – would probably cut sperm numbers too much.