They have made tiny designer compounds which smuggle themselves into sperm, saving their tails from wiggling. If a sperm cant swim, it has absolutely no way of naturally fertilising a womans egg.
The key advance raises the prospect of a fast-acting pill or a nasal spray that the man could take hours or perhaps just minutes before sex. Researchers believe its effects has on off within days, meaning he would again be rich. By contrast, women are typically advised to stop your Pill weeks actually months before trying to conceive.
Last night, family planning experts said a reversible male contraceptive could benefit millions of couples where the woman cannot take the Pill for medical reasons.
And it would save men from being trapped into having children they didn't want, they . With global sales of contraceptives topping 13?billion a year, the market with a reversible male contraceptive could be huge, but some cast doubt on the idea of a male pill, doubting women will trust men consider it.
Lead researcher Professor John Howl, of Wolverhampton University, a week ago described how effective their sperm-stopping agent had been in lab tests.
He said: The effects are startling and almost instant. As soon as you take healthy sperm and add our compound, within a few minutes the sperm basically cannot move.
Male infertility is usually the result of poorly moving sperm, called low motility. Using this, the Wolverhampton team, together with Portuguese researchers, resulted in a compound called a cell-penetrating peptide, which gets inside sperm and brings in order to a standstill. Prof Howl said: This is usually a totally unique approach nobody else has ever carried this out before.
Peptides are short chains of aminos that can influence how human cells work. They occur naturally but biochemists can make synthetic versions. Prof Howl and colleague Dr Sarah Jones first demonstrated that certain cell-penetrating peptides could smuggle themselves inside sperm cells, for being a Trojan horse.
Then they teamed up with IVF experts at Aveiro University in Portugal, who had identified the key protein responsible for putting the wiggle into sperm tails.
The two universities developed a bespoke peptide which turns that protein off. They tested decided in the petri dish on bovine and human sperm, with similarly impressive results, all of which will soon publish their last.
Prof Howl said they hoped to start live animal tests in two to three years, thanks in part to a 175,000 Portuguese grant. It typically takes three to 5 years generate a new drug to promote after animal trials, the actual final product could be available as early as 2021.
Prof Howl said ended up being too early to say if the outcome would turn into pill, a nasal spray or a sub-skin implant, but these people all methods.
John Guillebaud, emeritus professor of family planning and reproductive health at University College, London, said a reversible male contraceptive prospective of enormous benefit intercourse is a couples, pertaining to example those for the woman cannot take the Pill for medical reasons with regard to due to migraine with aura or perhaps increased risk of blood clots.
He added: It would also help men who wants to have power over their own fertility for example, for making sure they are not trapped into having a young child by a person who says she is on the Pill, but isnt.
An Anglia Ruskin University study found half of 134 women questioned were concerned their partner would forget for taking a contraceptive, but Prof Guillebaud, who's behind another male pill venture, said this the widely held myth. He cited a bigger survey of 1,894 women, conducted in Scotland, China and South Africa, which found only 2 per cent would not trust their partner.
Professor Geeta Nargund, medical director of CREATE fertility clinics, said: If this proves as well as effective, I know women would welcome the concept. Its about time men took responsibility for contraception.