Parents will be targeted by a new campaign to encourage sperm and egg donation to stave off a growing shortage that could cripple fertility treatment.

Plans to give children conceived by artificial insemination the right to seek out information about their donor 'parents' when they grow up have raised fears that donors will be put off getting involved.

Now a new advertising campaign is seeking older men and women who may have already had their own families, and have a mature understanding of the idea of parenthood, to share their good fortune with the infertile. Until now, medical students attracted by the £15 paid per sample have been a key source of donors.

The adverts, launched on Wednesday, will also aim to tackle myths surrounding donation, including the idea that donor children could one day try to pursue their biological parents for financial help: in fact, donors will continue to have no legal or financial obligation to the child, nor be obliged to meet them.

Men aged 28-45 and women aged 28-35 will be targeted in the campaign, to be launched by public health minister Melanie Johnson. Female donors tend to be older because of the complications and commitment involved in donation, which involves invasive procedures to retrieve the eggs.

Fertility doctors have warned of the serious risks of a shortage of donors already, which could be compounded when their anonymity is lifted in April.

Waiting lists for treatment are around five years, while in a recent survey nine out of 10 clinics said they were unable to meet demand for eggs despite around 1,100 women donating a year - compared with 226 men who donate sperm. Around 2,000 babies a year are born from donor insemination.