The bank, based at Birmingham Women's Hospital, now plans to appeal to male pride to boost donations.
"If I advertised saying 'Men, prove your worth, show me how good you are', then I would get hundreds of donors," chief executive Laura Witjens told the Guardian.
"That's the way the Danish do it. They proudly say, this is the Viking invasion, exports from Denmark are beer, Lego and sperm. It's a source of pride," she said.
The bank had received a 77,000-pound grant from the UK Department of Health to get up and running, but it will now be funded independently of the government. It was created to help tackle the shortage of donors which often drives patients overseas or to unregistered services.
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Donors must have strong sperm to qualify, and Witjens said many men were either put off or rejected after coming forward.
Men need to attend the clinic twice a week for three or four months and have a wide range of tests before being registered.
"Then the crux is having your sperm frozen and then tested, and that's where most men fail - about 80 to 90 per cent," Witjens said.
However, a donor is not the legal parent and is not named on the birth certificate.