Just 4% of men who apply to be sperm donors in Denmark and the US – from which the UK takes over half its donations – get through the process, new research shows.

The British expert behind the study said the UK’s system for sperm donation is flawed and more must be done to make it easier for men to donate.

Figures released in November show that more than half of men (52%) newly registered in the UK as sperm donors are from overseas, with the US and Demark the greatest exporters to Britain.

This is up from around a quarter (22%) in 2010.

With such a heavy reliance on imported sperm, a team of researchers led by the University of Sheffield decided to look at data on who donates.

They examined figures from one of the world’s largest sperm banks, Cryos International, on 11,700 men from Denmark and the US who applied to be donors.

The findings, published in the journal Human Reproduction, found that just 3.79% of the men (444) were accepted as donors and had samples frozen and released for use.

Most of those who initially applied either cancelled their application, failed to respond, did not attend an appointment or did not return a questionnaire.

Others had a health issue that meant they could not donate, some failed a screening test and others did not have enough mobile sperm.

Lead author of the study, Allan Pacey, professor of andrology and head of the department of oncology and metabolism at the University of Sheffield, said he hoped the study would help improve recruitment and retention processes.

On the fact so few men end up donating sperm for use, Prof Pacey told the PA news agency “you’ve got to really attract a huge number to even apply in the first place to get to the right numbers at the end”.

He added: “One of the criticisms of companies like Cryos is that they’re flooding the market with sperm and they don’t uphold the same standards.

“But they absolutely do, according to what we found in this paper – it’s just really, really hard, wherever you are, to recruit.”

He said not being able to remain anonymous in the UK is a barrier to some men donating, adding that his own experience of running a sperm bank also saw just 4% of men ending up as donors.

“In the UK, you can only become a donor if you agreed to be identifiable and there simply aren’t enough guys in the UK that are willing to do that, or we haven’t managed to tempt them enough, because we haven’t got an advertising system that targets them,” he said.

“They tend to be older men, men that have completed their own families.

“I just don’t think that the UK system is set up in the right way.

“It relies on individual donors thinking of the idea and then contacting their clinic, which may be miles away from them.

“If you live in Inverness are you going to travel to Aberdeen to donate?

“I think we need to change the system  – we need a system like the blood donation one where you can go to a local hospital or there are donor sessions in village halls, and it’s much easier.

“To donate sperm now, you’ve often got to travel to the local sperm bank, which may not be where you live.”

He said if researchers “can study donor recruitment like this, we might be able to change it so that it becomes more efficient or cheaper.”

Asked why most donations to the UK are from Denmark and the US, he said: “There is something about Danish men that I think is very different, they are much more altruistic, much more open, much more relaxed about this kind of thing.

“In the States, I don’t know the answer, but there are big sperm banks all over the United States.”

In the UK, sperm donors can receive up to £35 per clinic visit to cover expenses, with more available if expenses for things like travel, accommodation or childcare cost more.

Cryos International says on its website it offers up to about £59 per donation, with a minimum of about £24

Dr Anne-Bine Skytte, medical director at Cryos International said: “If we can recruit donors more easily then this will help keep costs down for patients in the UK and elsewhere who often buy donor sperm with their own money because it’s not funded by the NHS.”

Any man in the UK interested in donating sperm should contact their local licensed clinic, sperm bank or look on the Human Fertilisation and Embryology Authority (HFEA) website.

Clare Ettinghausen, HFEA director of Strategy and corporate Affairs, said: “HFEA data shows that since 1991, donor conception has led to the birth of over 70,000 children and although the number of people choosing to donate sperm in the UK has remained consistent in recent years, the number of sperm imported into, and used for donation in the UK has increased. It’s possible this is in response to a lack of ethnically diverse donors available in the UK.”