Sexual identity is now big part of official government statistics in both in the US and UK.
In the UK we have the Office for National Statistics (ONS), and in the US there is National Health Interview Survey, which is the government’s premier tool for annually assessing Americans’ health and behaviours.
It is reported that there are around 9 million LGBTs in America, which is roughly the equivalent to the population of New Jersey, and in the UK, there is around 1.2 million LGBTs, the equivalent to the population of Birmingham.
Over an age-range from 16 to 74, 1% of women and 1.5% of men consider themselves gay/lesbian, and 1.4% of women and 1% of men think of themselves as bisexual. But, there is a clear gradient with age, with a much higher proportion in younger people, particularly in younger women.
However, same-sex sexual behaviour can come in all degrees of intensity, from a same-sex experience, which could be just a smooch in the dark, to a same-sex partner, who is someone with whom you have had any genital contact intended to achieve orgasm.
For women, the proportion who report having had some same-sex experience has grown dramatically over the past 20 years: from 4% in 1990 to 10% in 2000, and to 16% in 2010 – a massive change in behaviour over such a short period. But this is not all just girls kissing girls in imitation of Madonna and Britney Spears; around half report genital contact, and around half of these in the past five years, so that overall nearly one in 20 women report a same-sex partner in the past five years.
However, it is clear that there is a lot of experimental activity going on. Roughly, for each woman who has had a recent same-sex partner there are two more of the same age who have had some same-sex contact in their lives.
Men show a different pattern. In 2010, about 8% of 16- to 44-year-old men reported having had a same-sex experience: this is higher than in 1990, possibly associated with both better reporting and the decline in fear of HIV, but there have been no substantial recent changes.
However, the picture shows a clear peak of lifetime same-sex experience for men aged around 60, and then a dramatic drop in those around 70, a pattern not seen in women.
History might provide some explanation: men now aged around 60 were teenagers in the liberating 60s, when homosexuality was legalised, while men who are now around 70 grew up when same-sex male behaviour in men was illegal and frequently prosecuted. Much younger men, meanwhile, would have come to adulthood in the more sober era of HIV.
Overall the proportion of people with same-sex experience is far higher than the proportion who identify themselves as gay and bisexual.
This must mean that many same-sex contacts are by people who do not consider themselves gay or bisexual.