We are told that the orgasm gap - that lesbian and bisexual women have more orgasms than heterosexual women - is a great injustice. For example, one study (which used an online survey and which many articles on the "orgasm gap" cite) found that 86% of lesbian women usually-always orgasmed when sexually intimate, but only 65% of heterosexual women.
Yet, the observant reader might've noticed a complexity here: the proportion of sexual encounters during which one orgasms is not the same as the number of orgasms one has. So this term, "orgasm frequency" is potentially misleading.
The paper cited as evidence for the orgasm gap asked participants: "During the past month, how often did [you]/[your partner] reach orgasm when you and he or she were intimate?’’ (1 = Never, 2 = Rarely, 3 = About half of the time, 4 = Usually, 5 = Always). Participants could also indicate‘‘not applicable, we were not intimate,’’and these participants were excluded from the dataset."
So whether someone had sex once in the past month or every day in the past month, or even multiple times per day in the past month, is not reflected in the data. Nor are people who didn't have sex in the last month.
To estimate the total number of orgasms one had during sex in the past month, one could make certain assumptions.
To start with, based on Figure 1, Reports of own orgasm frequency during past month for gay, lesbian, bisexual, and heterosexual men and women, among heterosexual women, 33% always orgasmed, 32% usually orgasmed, 17% orgasmed half the time, 10% orgasmed rarely and 8% never orgasmed (numbers don't add up to 100% due to rounding). Meanwhile, among lesbian women, 59% always orgasmed, 27% usually orgasmed, 8% orgasmed half the time, 3% orgasmed rarely and 3% never orgasmed.
Always orgasming could be assigned a 100% orgasm frequency, usually orgasming a 75% frequency, half the time 50%, rarely 25% and never 0%.
Based on these numbers, one could derive the probability of orgasm per session, like so:
Heterosexual women have a 0.68 probability of orgasming during sex, while lesbians have a 0.84 probability of such.
Note that this is the probability that a woman has at least one orgasm, so multiple orgasms would be reflected only once. The original paper does not talk about multiple orgasms, and in any case, Karen et al (2017) report that men had a greater desire to increase their frequency of multiple orgasms than women in mixed-sex relationships, who in turn reported a lower desire for multiple orgasm than women in same-sex relationships, so inasmuch as we are concerned about the "orgasm gap" as leading to lower sexual satisfaction (as opposed to just being a way to bash heterosexual men), multiple orgasm is relatively unimportant. Note the curious fact that while men orgasming more frequently is supposed to be an injustice to women, women actually have less of a desire for multiple orgasms than men, which is something I will come back to later.
Now, we need the other half of the equation - how often lesbian and heterosexual women have sex.
I found 2 studies on this - a 1983 book which was co-authored by Philip Blumstein and Pepper Schwartz (of course), but also a more recent 2021 one "debunking" lesbian bed death. In the latter, in the matched sample, 3% of heterosexual women reported having sex 8+ times per week, 8% 5+ times, 24% 3-4 times, 34% 1-2 times, 20% 2-3 times a month, 7% once per month, 4% once every few months and 0% no sex at all. The corresponding figures for lesbians: 2% of heterosexual women reporting having sex 8+ times per week, 5% 5+ times, 11 3-4 times, 34% 1-2 times, 25% 2-3 times a month, 12% once per month, 10% once every few months and 1% no sex at all.
Once again, certain assumptions must be made to get an average number of sex sessions per month (to match the former study, which asked about sex in the last month). Assuming, for simplicity, 4 weeks a month, 8+ times per week can be coded as 10 times a week, 5+ times a week as 6 times a week, 3-4 times a week as 3.5 times a week, 1-2 times a week as 1.5 times a week, 2-3 times a month as 2.5 times a month and once every few months can be 0.33 times a month.
We derive an average number of sex sessions per month for both populations, then multiple this by the probability of orgasm per session to derive a number of sex sessions with orgasms per month, as below:
As we can see, though lesbians are somewhat more likely to orgasm during sex than heterosexual women, because they have sex overall, heterosexual women are still having more sex sessions with orgasms than lesbians.
In any event, sex for women is not as orgasm-centric as it is for men, so it is curious how people go on about how much of an injustice the orgasm gap is. As noted earlier, women want multiple orgasms less than men, which suggests that orgasms are less important to women during sex than to men.
At least one paper also finds that "Women valued their partner’s orgasm more than their own", another found that "Lack of orgasm does not mean the absence of sexual enjoyment" and qualitatively, some women report that they can have good sex without an orgasm, or that not having an orgasm is no big deal. Similarly, women report diminishing marginal utility from increased orgasm consistency, which is why "women can still feel satisfied if they don’t orgasm all the time". Given that we know that women have sex for a lot more reasons than men do, all this is not surprising.
In short, the orgasm gap is a myth because straight women have more sexual episodes involving orgasms than lesbians, and anyway orgasms are not as important to women as to men.