Having more, rather than less sex could improve the quality of sperm with damaged DNA, suggests a study on men and fertility problems.

The study, involving 118 men in Australia, found that having sex every day for a week significantly reduced the amount of DNA damage in their sperm.

Previous studies have linked better sperm quality to higher pregnancy rates.

The research was announced Tuesday at a meeting of the European Society of Human Reproduction and Embryology in Amsterdam.

Dr. David Greening, who runs a private fertility clinic in Sydney, Australia, and a group of research colleagues, told the men to have sex every day for a week.

After seven days, the doctors found that in 81 per cent of the men, there was a 12 per cent decrease in the amount of damaged sperm.

Many fertility experts suggest men abstain from sex before their partners have in-vitro fertilization, to try to elevate their sperm counts.

Sperm quality can also be improved if men don't smoke, and drink moderately, exercise or get more antioxidants.

Since concluding the study, Greening said, he now instructs all couples seeking fertility advice to start by having more sex.

"Some of the older men look a little concerned," he said.

"But the younger ones seem quite happy about it."

Experts think sex helps reduce the DNA damage in sperm by getting it out of the body quickly; if sperm is in the body for too long, it has a higher chance of getting damaged.

Some experts said that while Greening's research is promising, it doesn't prove that daily sex for men with fertility problems will actually produce more babies.

Greening said he and his colleagues are still analyzing the study data to determine how many women got pregnant.