Before splitting anything by gender, look at the whole population: a long-term partner is the top major reason, and casual sex sits near the bottom. These don't sum to 100% because they aren't either/or — the same person can want a relationship and be open to casual. That overlap is exactly why the "82% want love / 18% want sex" framing (see the last group) is a category error.

Casual sex is the one reason where men and women diverge — men out-cite it by about two and a half to one. On the other major reasons (long-term partner, casual dating, friends) Pew found no significant gender gap. So the honest story isn't "men want sex, women want love" — both rank a relationship first; men simply layer more casual openness on top. It's an overlay, not a different species.

Both sexes want the man taller — but women's pull is the stronger one, and it shows up in real couples: the man is taller in ~92% of couples — a few points above the ~90% that random pairing of the height distributions alone would produce (Stulp), while the sharper sign is how rare the reverse is: female-taller couples turn up roughly 14× less often than chance (Gillis & Avis found 1 in 720, vs ~1 in 50 expected). The catch the height-pill misses is that the curve bends. Success with height is curvilinear, not linear: the very shortest men are penalized, but the optimum is only moderately above average, and extremely tall men get screened out by shorter women too. A window, not a ladder — which is why "it's over under six feet" is fatalism, not data. See the Height Pill →

In first-time hookups about one in nine women orgasm, versus two-thirds in committed sex. This helps explain why lower casual openness can be rational rather than prudish: when researchers held expected pleasure and anticipated stigma constant, the gender gap in accepting casual-sex offers largely vanished. Women aren't less interested in pleasure — they're less interested in the version of it that reliably underdelivers.

The broader gender gap persists beyond the hookup context: ~95% of heterosexual men usually orgasm versus ~65% of heterosexual women when sexually intimate. So the Armstrong chart can show that relationships improve women's odds without implying commitment fully solves the gap. Casual isn't the only place the deal is lopsided; it's just the most lopsided.

This is the demand asymmetry made personal, and it cuts both ways. Women are far more likely to feel buried in attention; men are far more likely to feel invisible for the lack of it. Same market, opposite complaints — which is also why "she feels like a body, he feels like a wallet" has a quieter cousin: she feels swarmed, he feels ignored.

Read this as a baseline-vs-subgroup comparison, not a clean gender split: the all-user bars already include these women, and Pew doesn't publish a tidy men-vs-women breakdown here — but women under 50 run well above the overall rate, and Pew reports men experience all three at lower rates. This is the "danger" half of why casual openness differs: the downside — harassment, threats, unsolicited explicit content — concentrates on younger women. Naming the male attention deficit above doesn't cancel this; both are true at once.

No-sex-in-a-year among young adults roughly 2.4×ed in a decade — and the rise skews male. Ueda et al. (2020, JAMA Network Open) put men aged 18–24 reporting no sex in the past year at 18.9% → 30.9% between 2000–02 and 2016–18 — a far steeper climb than women the same age. (Single-wave young-men cells are small, so read the exact figure as directional — Tier 2.) It's the attention deficit made literal: more young men aren't just feeling ignored on the market, they're falling out of it.

Women wanted roughly 69% of the marriages that ended — though that figure rests on just 92 marital breakups in the panel (95% CI 61–78%). The surprise: non-marital breakups ran about 56% women-wanted among cohabiters (~53% among never-cohabiting couples) — neither significantly different from 50/50. So "women always leave" is really "women leave marriages more" — the gap is specific to the institution, not to women, which points at marriage carrying costs wives disproportionately feel rather than a simple branch-swing instinct.

Two things break the "every partner chips away at bonding" story. First, the biggest jump is from 0 to 1 — having any premarital sex, not the marginal extra partner — which points at who stays at zero (highly religious, traditional, already low-divorce) rather than a dose effect. Second, it's non-monotonic: women with 2 partners divorce more than those across the 3–9 band (which sits flat around 24–26%, not a clean step). The raw data simply don't show the monotonic dose-response a per-partner "bonding depletion" would require. The association is real but confounded — and the "oxytocin runs out" mechanism underneath the claim is pseudoscience. See the full duality →

Initiation is male-default, and not narrowly: across four U.S. cities, ~81% of first messages came from men, and women's average reply rate ran under 20%. It's the demand asymmetry from the attention chart seen from the other side — men do the reaching, women do the selecting. The pattern repeats off the apps: marriage proposals run ~95%+ male, and the man still pays the first date about three-quarters of the time. What this chart deliberately can't show is the popular claim that men are initiating less than they used to — no one has measured initiation as a time series, so we don't chart it. The withdrawal shows up only in downstream outcomes — the two charts below. See the model: The Men's Strike →

The permanent-single class is real Tier-1 data, not a meme: never-married-at-40 more than quadrupled in four decades, and Pew projects ~1 in 4 of today's young adults will never marry. The gender twist matters. Under 30, men are the more-single sex — Pew puts it at 63% vs 34%, though the GSS gap is far narrower (~56/54), so trust the direction, not the exact spread. But it flips with age: by 65+ women are the more-single sex by more than 2:1, because men remarry and women outlive them. The young surplus of single men becomes an old surplus of single women.

Most checked-out singles say they simply have other priorities or like it that way — but read these as self-reported: the flattering answers run high, the stigmatized one runs low, so the involuntary share is almost certainly understated. The one reason that splits sharply by sex is exactly that stigmatized one — "no one would be interested in me": men 26% vs women 12%, the involuntary-singlehood tell. And not-looking is itself gendered by age: among singles 40+, 71% of women aren't looking vs 42% of men — the female exit the apps never see, and the reason a "men's strike" lands on a market many women have already left.

This one we deliberately don't chart with hard numbers, because the evidence is genuinely mixed. Belief in the double standard is widespread, but controlled studies often find it weaker than expected — sometimes men and women both get judged for high partner counts. Still, it bites where it counts: anticipated stigma measurably lowers women's stated willingness to accept casual sex (Conley et al., 2013), which means the openness gap above is probably understated. The asymmetry is real as a social perception that shapes behavior — but anyone who tells you it's been cleanly measured at some exact ratio is selling you a number that doesn't exist.