Condoms made to international standard sizes are too large for many Indian men, a survey has found.
A two-year study by the Indian Council of Medical Research found that more than half of the Indian men measured had penises shorter than international standards for condoms.
It has led to a call for condoms of mixed sizes to be made more widely available in India, where over 2 million people are estimated to live with HIV.
Over 1,200 volunteers across the country had their penises measured precisely, down to the last millimetre, according to a BBC report.
The scientists concluded that about 60% of Indian men have penises 3-5cm shorter than international standards used in condom manufacture.
Doctor Chander Puri, a specialist in reproductive health at the Indian Council of Medical Research, told the BBC there was an obvious need in India for custom-made condoms, as most of those currently on sale are too large.
Currently around one in every five times a condom is used in India it either falls off or tears, an extremely high failure rate.
Puri said that since Indians would be embarrassed about going to a chemist to ask for smaller condoms there should be vending machines dispensing different sizes all around the country.
He said: "Smaller condoms are on sale in India. But there is a lack of awareness that different sizes are available. There is anxiety talking about the issue. And normally one feels shy to go to a chemist's shop and ask for a smaller size condom."
But Sunil Mehra, former editor of the Indian version of Maxim magazine, retorted: "It's not size, it's what you do with it that matters.
"From our population, the evidence is Indians are doing pretty well."