Bill Gates has already put some of his money toward building a better toilet, and now he’s turning his attention to another kind of bodily function. The Microsoft billionaire is putting up money through the Bill and Melinda Gates Foundation in hopes of spurring enterprising inventors to make a better condom.

Though condoms are cheap to make and fairly reliable both for contraception and the prevention of sexually transmitted diseases, many men do not use them due to a perceived trade-off between protection and pleasure.

“Is it possible to develop a product without this stigma, or better, one that is felt to enhance pleasure?” the Gates-backed organization Grand Challenges asks. “If so, would such a product lead to substantial benefits for global health, both in terms of reducing the incidence of unplanned pregnancies and in prevention of infection with HIV or other STIs?”

Until May 7, Grand Challenges is accepting proposals for next-generation condoms. For winners of an initial $100,000 grant, there’s the possibility for an additional $1 million in funding later on.

“Condoms have been in use for about 400 years yet they have undergone very little technological improvement in the past 50 years,” Grand Challenges says.

Actually, the history of the condom may go back even further than four centuries.

It’s hard to pinpoint just when the first condom was used. Some researchers have suggested that the ancient Egyptians used condoms -- and even dyed them in various colors -- but evidence for this is scarce. There are more solid reports of glans condoms, which covered only the head of the penis, being used amongst the upper classes of Asia before the 1400s. Such condoms were made of intestine, oiled paper, animal horn or tortoise shell.

A female condom of a sort crops up in an ancient story about Minos, the king of Crete, who was supposedly cursed such that his semen was full of scorpions and snakes, which needless to say would complicate things a bit. The scorpion-laden emissions problem was solved by inserting a goat bladder into the vagina of Minos’s sexual partners, according to the Greek writer Antoninus Liberalis.

One of the oldest incontrovertible descriptions of a condom comes from 16th-century Italian physician Gabriele Falloppio, who lent his name to the Fallopian tube. Amidst a roaring syphilis epidemic, Falloppio recommended that men sheath their penises in specially treated linen, tied with ribbons. The doctor is said to have tested these linen condoms on 1,100 men, all of whom supposedly avoided contracting syphilis.

The oldest condoms ever found were dug up in the cesspit -- or big toilet -- of Dudley Castle, an English ruin, in 1985. Made of fish and animal intestine, the condoms were most likely dropped into the cesspit sometime in the mid-17th century. The condoms were only able to survive thanks to the fetid, airless environment of the castle toilet, which prevented the growth of bacteria.

Until the industrial production of rubber was perfected in the mid-19th century, most condoms were made from animal intestines. One recipe from that era, quoted by About.com, describes how to make a condom from the large intestine of a sheep:

“Soak it first in water, turn it on both sides, then repeat the operation in a weak ley (solution) of soda, which must be changed every four or five hours, for five or six successive times; then remove the mucous membrane with the nail; sulphur, wash in clean water, and then in soap and water; rinse, inflate and dry. Next cut it to the required length and attach a piece of ribbon to the open end.”

The first synthetic condoms were made of rubber, and usually only covered the head of the penis, but this required extensive tailoring and fitting; the current full-sheath model allowed for ease of production. Latex, which is derived from rubber, was the next great advance in condom manufacturing, being easier to make, stronger and thinner than rubbers.

But what will the next generation of condoms look like? One company in California is building the Origami condom, a collapsible silicone affair that’s designed to create pleasant sensations. Researchers at the University of Washington are working on a high-tech condom that uses nanoscale fibers that could also deliver drugs to protect against STIs or deliver contraceptive benefits.