American research suggests that eight per cent of men and seven per cent of women describe themselves as gay, lesbian or bisexual.
The results come from Indiana University’s Center of Sexual Health Promotion, which surveyed almost 6,000 adults.
Last month, a British study of 450,000 adults claimed that just 1.5 per cent were lesbian, gay or bisexual.
However, critics pointed out that the British research had taken place over the phone or on doorsteps, where people may be less likely to declare their sexual orientation.
The American survey is said to be the country’s biggest poll on sexual health and behaviour for 16 years.
While only seven per cent of women and eight per cent of men called themselves gay or bisexual, many more said they had experienced a same-sex sexual encounter.
Fifteen per cent of men between the age of 50 and 59 said they had received oral sex from another man at least once in their lives.