is over 5,000 years old?

That's right, some of the first forms of birth control

date back to around 3,000 BC,

and while the condom has made some strides

since the Bronze Age, men still don't have

a much better option all these millennia later.

Besides a vasectomy.

Especially compared to the pills,

IUDs, and implants available to women today.

So why don't we have birth control for men?

In 2002, researchers asked

more than 9,000 men across four continents

whether they'd be willing to use contraception

capable of preventing sperm production.

Over half said yes.

So the problem isn't lack of interest,

it's partly human biology.

Women ovulate just one or two eggs each month.

Men, on the other hand, produce sperm daily,

and it's not just one or two.

There's literally hundreds of millions of sperm

produced each day, so because there's so many

sperm produced, actually, you can reduce your sperm number

over 90% and still be completely fertile.

Narrator: To reach infertility, a man's sperm count

needs to be somewhere around 1 to 10 million

per milliliter, but getting there is near impossible,

at least without side effects.

That's because sperm count is tied

to the production of testosterone.

In the past, researchers tried decreasing testosterone

in an effort to decrease sperm count.

The problem is you don't have any libido,

you have very little testosterone to act on other tissues

and so forth, and so the side effects were so dramatic

that it really wasn't ever

going to be a contraceptive pill.

Narrator: Scientists also tried using different compounds

that attack the cells that produce sperm.

But again, biology got in the way.

Germ cells, as they're called, developed inside

a fortress-like structure within the testes.

So literally, nothing can get through it.

There's been a lot of small molecule studies

to try and actually attack the germ cell

to stop it from working.

Literally, I can think of 10 or 15 different compounds

that actually have been developed to do that,

but they don't work because of that barrier.

Narrator: But the complex male anatomy

isn't the only problem. It's also funding or lack thereof.

In 2002, two big pharmaceutical companies

took interest in male contraception, Schering and Organon.

And together they funded a large clinical trial

on a hormone-based contraceptive,

offering hope that a pill backed by Big Pharma

might be on the horizon.

Then these two companies became, as you know,

acquired by bigger company, and then even bigger company,

so now they are merged in huge companies,

and women's health is still a priority

in many of the companies,

but men's health became part

of the general matter of health.

And therefore, the development of contraception

becomes a really very low priority.

Narrator: According to Dr. Wang,

male contraception was also too risky

for Big Pharma at the time.

The long-term side effects were unknown.

Companies were concerned that women might not trust it,

and despite the survey results, it was unclear whether men

would actually use a hormone-based contraception.

Today, the limited funding comes mostly from

government agencies like the National Institutes of Health.

But there are in fact some promising lines of research.

Dr. Wang is working on a gel that can lower testosterone

where it matters, in the testes where sperm is produced,

while keeping testosterone levels normal elsewhere.

That means low sperm count and, more importantly,

no major side effects.

We have preliminary studies to show

that if we give the gel and if the man applies the gel,

90% of the men will reach the level that you talk about,

1 million per mil.

And Skinner is pursuing a new approach,

shutting down Sertoli cells,

which are a part of that impenetrable barrier

that houses germ cells.

So if you shut down the Sertoli cell,

then you shut down the sperm production.

Narrator: But perhaps most promising

is a sort of reversible vasectomy that's in the works.

So they have this ability to inject this gel

into what's called the vas deferens,

and it makes this plug, so then essentially

it does the same thing, but you're not cutting it.

Then believe it or not, you can actually

inject this chemical mixture, which will dissolve the plug,

and so then you can get your fertility back.

Narrator: But as promising as these approaches may be,

they're still years, if not decades, out, Skinner says.

And without more funding, some of them

may never hit the market.

So at least for now, men are left with few options.

Irreversible vasectomies, pulling out ,

and that slightly updated Bronze Age invention.