Scientists are seeking couples to take part in a trial of a new contraceptive injection for men.
A team from Edinburgh University is involved in the World Health Organisation research into the jab.
The scientists claim it can give much better protection against pregnancy than condoms.
And it is hoped the work could help pave the way for such a form of contraception to become more widely available.
Researchers at the University of Edinburgh are hoping to recruit 20 couples from the south east of Scotland to take part in the study - which is being run by the World Health Organisation.
Fully reversible
The injections contain the hormones testosterone and progesterone, and are given to the men every two months.
Sperm counts fall rapidly, and when these are low enough couples taking part in the trial would use the jabs as their method of contraception for a year.
Scientists also stress that the effects of the injections are fully reversible.
Professor Richard Anderson of Edinburgh University's reproductive and development sciences division said: "If this trial is successful I imagine there would be interest in looking at marketing the injection as a male contraceptive.
400 couples
"Even if not all men would be keen on an injection, there would definitely be a market to make such a treatment available."
The study will involve 400 couples from 10 centres across Europe, Asia, South America and Australia.
And Professor Anderson said: "This larger study is needed to add to the evidence as to how good these longer acting injections are and what couples think about it."
The study is looking to recruit couples where the man is aged under 45 and the woman is under the age of 37.
