London - Just who should take responsibility for birth control is a subject that divides many couples. There are only two forms of male contraception - condoms and vasectomies, and they have disadvantages.
Though condoms have a 98 percent success rate with perfect use, in reality and with human error, they prevent pregnancy only in 85 percent of cases - an unacceptable risk for many couples.
Vasectomies are designed to be a permanent form of contraception (though a reversal is possible) and involve otherwise healthy men going under the knife.
Female contraceptives, on the other hand, such as the Pill or implants are effective and reversible, though they can cause nasty side-effects such as weight gain, depression and blood clots.
So why are there not more options for men? The simple answer is biology, says Professor Peter Schlegel, head of urology at New York’s Cornell University and a top authority on male contraception.
“It is a lot easier to control one egg than the 100 million sperm a man produces every day. The potential for error is enormous and all it takes is for one sperm to get away for the treatment to fail. It is practically much more difficult.”
However, with 50,000 men having a vasectomy every year in Britain, there is clearly a market for male family planning and scientists around the world, determined to push back scientific frontiers, are trying to find new options.
Here, we round up the options on the horizon:
* A contraceptive injection given to men once a month could be as effective as the female Pill or condoms. The testosterone jab is administered in the buttocks and works by regulating two brain chemicals - follicle-stimulating hormone and luteinising hormone - which has the effect of blocking sperm production temporarily.
Testosterone is vital for sperm production, but if the body detects too much it shuts down its sperm production.
A two-year trial in China involving 1,000 men found the injections were 95 percent effective at preventing pregnancy. Six months after stopping the jabs, all but two of the men’s sperm counts were back to normal.
While the results seem promising, a third of the men dropped out, suggesting they were unwilling to undergo the ordeal of monthly injections and potential side-effects that include mood swings, lower sex drive and acne.
Furthermore, previous studies show Asian men are more responsive to testosterone than European, possibly because of their genetic make-up and lower body mass index.
So in the West an additional hormone such as progestogen may need to be added to shut down sperm production.
“Five percent of men will not get sperm count down to a level for it to be a reliable contraception,” says Professor Schlegel .
“In addition, there is a two to three- month time lag from taking the testosterone to stopping all sperm production, so couples would need to use another form of contraception until then.”
* Available: In five years.
British researchers are developing a male pill that prevents sperm from being released on ejaculation.
The pill uses compounds found in blood pressure and anti-psychotic medication used in the Sixties, which were found to have the side-effect of “dry ejaculation”.
These paralyse certain muscles in the male reproductive system, causing a temporary block of the release of semen while having no adverse effects on libido, sexual performance or sensation - so the man still has an orgasm, but produces no fluid.
Studies by researchers at King’s College Hospital, London, suggest the pill works within three hours and lasts for two days - so it is taken when required.
Professor John Guillebaud, Emeritus Professor of family planning and reproductive health at University College London, says: “This method has the potential to be a pre-coital pill, possibly working at full efficacy in two to four hours after it is swallowed.
“This could also help to reassure the anxious partner, since she could supervise him taking the tablet at supper ready for action at bedtime!”
* Available: With research funding, available in ten years.
* A 15-minute painless blast of ultrasound to the testes could provide six months of contraception, scientists have found.
This kills reproductive cells that produce sperm throughout the testes, reducing the sperm count to zero. The best results were seen using two ultrasound sessions of 15 minutes, two days apart.
Multiple treatments given a few days apart could be used for permanent sterilisation.
Researchers at the University of North Carolina have shown this works on rats and monkeys.
“Further studies are required to determine how long the contraceptive effect lasts and if it is safe to use multiple times,” says Dr James Tsuruta, from the university.
The benefit is that it targets only the testes, so there are none of theunpredictable side-effects experienced with hormones.
* Available: Research is continuing, but it will be some years before it is widely available.
A male contraceptive pill with no side-effects is being developed by scientists.
* The drug - BMS 189453 - works by temporarily impairing the body’s ability to use vitamin A, vital for the production of sperm. It takes between two and four weeks for sperm production to stop, but men would start producing sperm again almost as soon as they stop taking it.
Though vitamin A is also crucial for vision, researchers at Columbia University in New York, who are developing the pill, say it will not affect sight. Tests on mice have shown the pill is effective, with no side-effects.
“An additional benefit of our compound is that it can be taken orally, possibly once a day, avoiding the injection process,” says researcher Dr Wendy Chung.
Research suggests 55 percent of men would be willing to take a male pill. However, a British study published in 2010 found that women didn’t trust men to take a contraceptive pill every day.
* Available: Scientists hope to carry out long-term studies on humans within a few years.
* A breakthrough by British fertility experts could lead to a “genetic vasectomy”.
Edinburgh University scientists have discovered a gene called Katnal1 that is critical for the production of healthy sperm.
The discovery could lead to a jab of genes that would leave a man permanently sterile, or a drug that blocks the gene from working to be used as a temporary contraceptive. “If we can find a way to target this gene in the testes, we could develop a non-hormonal male contraceptive,” says Dr Lee Smith, at the Centre for Reproductive Health at the University of Edinburgh.
“The important thing is that the effects of such a drug would be reversible because Katnal1 affects sperm cells only in the later stages of development, so it would not hinder the early stages of sperm development and the overall ability to produce sperm.”
* Available: A widely available contraceptive based on this gene is a decade away.
* A gel injection that blocks and inactivates sperm could provide birth control for ten years.
The gel is injected into a tube in the scrotum called the vas deferens - the tube that sperm travels along during ejaculation.
It coats the walls of the vas deferens, partially blocking it so that fewer sperm can be released on ejaculation, and chemicals in the gel break the sperm cell membranes, so they are no longer able to fertilise the woman’s egg to start a pregnancy.
The gel injection, known as RISUG (Reversible Inhibition of Sperm Under Guidance), takes 15 minutes to carry out, and has been trialled in India. One study shows no pregnancies for between one and three years after a single treatment. Work on a similar product called Vasalgel is underway in the US.
Research suggests it works almost instantly, though precautions are suggested for the first ten days. Side-effects include swelling of the testes, and there have been concerns about the toxicity of the product.
* Available: One of the more promising options, which could be available within five years. - Daily Mail