The US government will soon start human trials of a male birth control gel, the National Institutes of Health (NIH) announced Wednesday.

Currently, the only approved male contraceptives are condoms or vasectomies, surgical procedures to block sperm.

There are myriad forms of birth control for women and they often come with complicated and disruptive side effects.

If it proves safe and effective, it would be the first new birth control for men since the condom was introduced in the 1800s.

The National Institutes of Health will soon have 420 couples test a male birth control gel with sperm production-blocking hormones that are absorbed through the skin

Between condoms and female birth controls, we now can make 99 percent effective contraception - when each is used properly.

But each comes with significant drawbacks.

Condoms themselves fail us only occasionally, but people fail to use them correctly much more often, leading to a failure rate of about 13 percent.

Failure to use a condom at all or to use one properly is a primary reason that 45 percent of pregnancies in the US are unwanted or unintended.

Female birth controls range widely in their effectiveness, but the most common forms, oral contraceptives, fail about nine percent of the time - again, usually because they don't get taken or don't get taken on time.

DOES HORMONAL BIRTH CONTROL INCREASE A WOMAN'S RISK OF DEPRESSION? Hormonal birth control does not increase women's risk of depression, research suggested in February 2017. Contrary to popular belief, contraceptive pills, implants or injections do not make women more likely to suffer from the mental-health condition, a study found. Lead author Dr Brett Worly from Ohio State University, said: 'Depression is a concern for a lot of women when they're starting hormonal contraception. 'Based on our findings, this side effect shouldn't be a concern for most women, and they should feel comfortable knowing they're making a safe choice.' The researchers blame platforms such as social media for making contraception complications seem more common than they are. Dr Worly said: 'We live in a media-savvy age where if one or a few people have severe side effects, all of a sudden, that gets amplified to every single person. 'The biggest misconception is that birth control leads to depression. For most patients that's just not the case.' The scientists add, however, certain women are at a greater risk of the mental-health disorder and should be monitored closely. Dr Worly said: 'Adolescents will sometimes have a higher risk of depression, not necessarily because of the medicine they're taking, but because they have that risk to start with. 'For those patients, it's important that they have a good relationship with their healthcare provider so they can get the appropriate screening done - regardless of the medications they're on.' The researchers reviewed thousands of studies investigating the link between contraceptives and people's mental health. Such studies included various methods of contraception, including injections, implants and pills. Participants in the trials were made up of teenagers, women with a history of depression and those who had given birth in the past six weeks. Advertisement

Implants, intrauterine devices (IUDs) and injections are all better than 99 percent effective, but they are more expensive than condoms and all require women to go through uncomfortable procedures and to introduce something foreign and long-term in their bodies.

Women have increasingly been clambering for the responsibility of preventing unintentional pregnancy to be more evenly distributed between the two people required to fertilize an egg.

This call has also become more urgent in recent years, as access to birth control, emergency contraceptives and abortion has been diminished for many women.

Perhaps for this reason, there have been more attempts to invent new male birth controls, but thus far they haven't made it to market, either due to clinical failures or lack of funding.

But now the NIH is throwing its weight behind trials of one such contraceptive.

'Many women cannot use hormonal contraception and male contraceptive methods are limited to vasectomy and condoms,' said study investigator Dr Diana Blithe, chief of the NIH's Contraceptive Development Program.

'A safe, highly effective and reversible method of male contraception would fill an important public health need.'

The new gel, called NES/T, is about as non-invasive as a medical product can get.

It contains two hormones - progestin and testosterone - that are absorbed through the skin when the gel is rubbed onto a man's back and shoulders.

Progestin - which is also found in most hormonal female birth controls - naturally blocks the action of the male hormone, testosterone, keeping the testes from producing sperm.

But testosterone is also key to male physical features and sex drive, so the gel also delivers a dose of replacement hormone.

The NIH will recruit 420 couples to try out the gel as their only form of birth control - ultimately, for a whole year, if all goes according to plan.

First men will slather up their shoulders and backs every day for between four and 12 weeks to make sure that they tolerate the product well.

During this time their sperm levels will also be measured (for up to 16 weeks if necessary).

Once they are consistently producing a low enough concentration of sperm for the scientists to consider NES/T 'contraceptive,' they'll start putting it to the test with their partners over the course of the next year.

If it works, there may be hope for freedom from the pill for women - but it will likely be years before the male birth control gel could hit the market.