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It is now 50 years since the pill was approved for contraceptive use. These days women have 10 methods of reversible contraception to choose from.

Men on the other hand, can either use condoms, or choose the permanent option of vasectomy.

Why has medicine failed in this department, and is this fair?

Carl Djerassi – one of the founders of the pill - is pessimistic about the prospects of such a product ever being made available.

The climate of liability that has overshadowed drug development since the 1970s, making pharmaceutical companies reluctant to open up new concerns in this area, while the potential profits are too small to justify the expense of research.

Meanwhile, scientists in non-profit areas of medicine have successfully created hormonal methods in the form of injections, skin gels and implants.

They have also discovered that ultrasound can cause temporary male infertility. Indian biomedic Professor Sujoy Kumar Guha has invented a polymer that can kill sperm when injected into the vas deferens, and can last 10 years. He explains how men have travelled from the west to his clinic in India, demanding the injection – showing just how frustrated some men are with the current lack of choice.

Hundreds of men have also taken part in medical trials for various methods, including Bill Crozier. He and his wife Rachael discuss why a reversible male contraceptive is so important to them.

Elaine Lissner, director of medical research programmes at the Parsemus Foundation and long-standing advocate of male contraception, explains that a male contraceptive will be reliant on the non-profit sector and government backing if it is ever to become available.