After championing affordable laptops for children in the developing world, designing more efficient toilet systems and fighting malaria with mosquito nets in Africa, Bill and Melinda Gates have set their sights on the next global concern they say needs attention: building a better condom.

Since stepping down as head of Microsoft, the world's former richest man has focused his energies on charitable causes close to his heart.

One of the initiatives that the Bill and Melinda Gates Foundation bankrolls is the Grand Challenges on Global Health, a series of grants in which the foundation lays out its aims for a project and offers funds for any group that can best meet the criteria.

One of the projects listed on the group's website Tuesday calls for submissions to "develop the next generation of condom."

The foundation is offering $100,000 in grant money to fund any group that can come up with a prototype "that significantly preserves or enhances pleasure, in order to improve uptake and regular use."

Condoms have been around for more than 400 years, but have had the same basic design without any major changes for much of the past 50 years.

As it stands, less than one in seven humans on earth currently use a condom for sexual activity. The Gates foundation says a "lack of perceived incentive for consistent use" is holding back wider adoption.

So they're pledging money to bankroll any design that manages to combat the general stigma against condoms — that they decrease sexual pleasure — in favour of a version that is neutral or even improves it, without sacrificing condoms' disease and pregnancy-fighting properties.

The plan sounds like it's light-hearted, but the Gates foundation is serious.  Condoms are one of the best weapons in the arsenal of medical experts to fight sexually transmitted diseases such as syphilis, HIV and others that kill tens of millions of people every year. Currently, more than 15 billion condoms are produced per year, and they're used by 750 million men worldwide.

The Gates foundation says any winning ideas that secure phase I funding of $100,000 US may be eligible for an additional $1 million in phase II if early results are promising.