Men and woman are being urged to donate their sperm and eggs to help couples who are not able to have their own biological children.

The Hertfordshire and Essex Fertility Centre, which treats patients from both counties, is appealing for more people to come forward and make donations.

The appeal comes after the UK’s first national sperm bank opened last week in Birmingham after shortages of sperm have lead to increases of imported sperm.

The Barnet-based centre has 18 sperm donors on its books who can donate up to 10 times, and also promotes egg sharing among women.

A woman can receive a free round of IVF if she is willing to share her eggs.

Centre manager Debbie Evans said: “The UK is one of the safest places to donate sperm and eggs.

“I think a lot of people were put off when donor anonymity was lost because people thought it would mean someone turning up on their doorstep in 10 years time, or being financially responsible.

“But it doesn’t mean that at all and it is one of the most selfless things you can do.”

Stevenage couple Lisa and John Leonard conceived their son Freddie using a sperm donor, although they did not use the Herts and Essex Fertility Centre.

Lisa, 38, said: “During the pregnancy I did have a few concerns about whether we would both feel Freddie was part of us.

“However from the moment we had our first scan he was definitely ours.

“It is the best thing in the world when John walks in the room and you see Freddie smiling at him.”