Demographics

Prevalence

Asexuals are currently thought to make up around 1–4% of the population. As with other sexual orientations though, it's difficult to get a precise idea of the prevalence of asexuality. This is due to studies relying to self-report data, and some issues more specifically related to asexuality as mentioned below.

Scientific studies that have been conducted on the prevalence of asexuality have tended to find that around 1% of the population is asexual [1–6]. It's likely, however, that the figures from these kinds of study are underestimates of the actual prevalence of asexuality. Some of the reasons for this are listed below.

To elaborate somewhat – this kind of restrictive definition excludes those whose orientation has changed over time, and it excludes everyone in the space between "never" and allosexuality. Both are groups of people who might much more closely identify with asexuality than allosexuality. In addition, such studies often do not define what is meant by "sexual attraction" in the first place. This is problematic because it's common for asexuals, before they identify as such, to believe they're feeling sexual attraction because they are mislabelling romantic, sensual, or platonic attraction.

A more recent GLAAD survey reported that among under 35s the percentage of asexuals is 4% [7]. This is in part due to the GLAAD survey using self-identification with asexuality rather than the more restrictive definition discussed above. It therefore includes people who are under the asexual umbrella but aren't strictly asexual (e.g. demisexuals). The lower age bracket of under 35s is also likely to mean that participants where more likely to be aware of asexuality before taking the survey.

Gender

Studies that look into the prevalence of different genders among the asexuality commonly find that the number of men is low compared to women [1,17]. In fact in some cases the number of men is even less than those that identify as neither men nor women [8]. The reason for this is not well understood at present. At least part of the answer could be that men face greater barriers to identifying as asexual (or more specifically, identifying as not experiencing attraction) than other genders. For example:

However, since sexual orientation is a result of the complex interplay between environmental and genetic factors, it's possible that men are genuinely less likely than women to be asexual. For example, it is already known that men are more likely to be exclusively homosexual than to be bisexual, whereas women are more likely to be bisexual than to be exclusively homosexual [9–11]. From an evolutionary perspective, sexual behaviour is precisely the area in which we might expect a difference between the sexes, so it would not be surprising if it turned out that men are in fact less likely to be asexual than women.

Current estimates from the 2016 Asexual Community Survey [8] have the following breakdown.

An important caveat to the Ace Community Survey figures is that they are subject to sample bias (being administered by word-of-mouth on the internet) and they only include people that self-identify as ace (so they could be affected by a barrier to men identifying as ace compared to women).

Biomarkers

One piece of evidence that asexuality is a distinct orientation comes from biomarkers associated with it – in a similar way to there being biomarkers associated with other non-hetero sexualities [12]. Below you can find discussion of some of these biomarkers that have been observed in asexuals, as well as comparison to other non-hetero sexualities. Of course, it should be noted that these are characteristics of the entire population of asexuals (within which there is substatial variation) and not of individuals. Some effects may also be statistically significant while having a small magnitude.

Physical characteristics

Studies have found a few physical characteristics to be more prevalent among asexuals. These include being shorter [1,2] and weighing less than non-asexuals [1], as well as asexual women being more likely to have a later onset of menarche [1,2]. Evidence also suggests that asexuals are more likely to have poor health [1].

Non-righthandedness

Asexuals are significantly more likely not be righthanded compared to heterosexuals, with a prevalence of over 25% [13]. This same effect of being less likely to be right-handed is found among homosexual individuals [14]. The evidence suggests that asexual men are more likely to not be righthanded even compared to homosexual men [13].

Fraternal birth order

There is statistically significant evidence that righthanded asexual men have more older brothers than righthanded heterosexual men; and that asexual women have fewer older brothers than heterosexual women [13]. Among men, the number of older brothers born of the same mother has been associated with an increased likelihood of being homosexual [15,16]. (The same pattern is not found in women and may only apply to righthanded men [13].) Homosexual and asexual men and women are each more likely to have fewer older sisters than their heterosexual counterparts [13].

Footnotes

  1. See Can I be asexual if I masturbate? for more details.

References