A striking finding of The Irish Times sex survey is that same-sex attraction among heterosexual women is far higher than previously thought, with 45 per cent of 17- to 34-year-old heterosexual women – nearly half – having been attracted to another woman.

Thirty-five per cent of 35- to 49-year-old heterosexual women and 24 per cent of women between 50 and 64 also indicated that they had experienced same-sex attraction. Yet 88 per cent of women respondents identified themselves as heterosexual.

“This ability to experience sexual attraction to the same sex as well as to the opposite sex is referred to as ‘sexual fluidity’,” says Dr Geraldine Moane, director of the higher diploma in psychology at University College Dublin. “Research has generally found that a much higher percentage of women experience attraction to other women compared with the percentage of men who experience attraction to other men.”

One reason is that women’s sexual pleasure is not as focused on sexual intercourse, making women more open to what constitutes sexual pleasure and intimacy.

“Heterosexual men are more focused on heterosexual intercourse, and there is a link between heteronormativity and masculinity, so there may be more of a taboo among men about same-sex attraction,” she says.

Women are also more likely to identify as bisexual rather than lesbian, while the converse applies to men.

Lesbians indicate a very high level of enjoyment of sex, with 68 per cent indicating that they “really enjoy it”, compared with just under half of heterosexual women (49 per cent). Also, just over half of lesbians (51 per cent) report being “very happy” with their sex lives.

So the people who enjoy sex most are lesbians (68 per cent) and heterosexual men (69 per cent), followed by bisexual men and women (61 and 58 per cent respectively), and homosexual males (54 per cent) and heterosexual females (49 per cent).

When asked about happiness in their sex lives, bisexual males had the lowest “very happy” score (25 per cent), with 51 per cent of lesbians being “very happy”. Heterosexual and homosexual men were equally “very happy” at 30 per cent for both.

Why are lesbians happiest?

So what is it that makes lesbians the happiest? Moane believes it is because this group is also more likely than heterosexual women to have sex three or more times a week (25 per cent), to use sex toys (79 per cent) and to have engaged in BDSM (27 per cent). All lesbian repondents said they had engaged in oral sex (compared with 98 per cent of sexually active heterosexuals), while 40 per cent had had anal sex.

However, it is important to say that these figures are based on a low number of respondents (173).

Gay men who took the survey were more moderate in their enjoyment and happiness, but were still happier and having better sex than heterosexual and bisexual men. Among gay men, 54 per cent “really enjoy” sex and 40 per cent enjoy sex “mostly”. Thirty per cent of gay men are “very happy” with their sex lives and 39 per cent are “somewhat happy”.

Gay men are having the same frequency of sex as heterosexual men, but are more adventurous. Two out of three use sex toys, a third have engaged in BDSM and all have had oral sex (95 per cent of them within the past year) and 96 per cent have had anal sex. Eight out of 10 gay men in committed relationships are monogamous, with “a notable” number (12 per cent) saying they are in an open relationship.

More female bisexuals are “very happy” with their sex lives than male bisexuals (40 per cent, as opposed to 25 per cent). Bisexuals are more likely to have engaged in oral sex and anal sex and are less likely to be monogamous, which reflects a more adventurous attitude towards sex.

The Irish Times sex survey was conducted on irishtimes.com over the course of a week in June 2015. A total of 12,639 participants completed the survey (a 71 per cent completion rate), with 12,134 responses used in the follow-up analysis. Over 500 responses were excluded, the vast majority because the participant was under the age of 17 (below the required age to take part) or where it was obvious that false information had been provided. Click here to view the full results, with interactive graphics.

The survey was carried out among self-selecting individuals. It is not a weighted survey and does not purport to be accurately representative of the wider population, biased as it is towards certain age groups (over two-thirds of those who took the survey were between the age of 24 and 50) and towards those who are more sexually active. Therefore all results should be seen as indicative rather than definitive.