On August 26, 2026, PsyPost reported on a study in the Journal of Sex & Marital Therapy that puts a number on something clinicians have long observed but never quantified: women diagnosed with hypoactive sexual desire disorder — a persistent absence of sexual thoughts or desire causing personal distress — still engage in roughly 2.5 sexual events per month before any treatment begins. The authors, Nikita Guptan and James A. Simon of IntimMedicine Specialists in Washington, D.C., call the behavior "mercy sex": consensual participation not driven by personal arousal but by a perceived relationship obligation. The paper, "Quantification of 'Mercy Sex' in Heterosexual Women," was published in volume 52 of the journal.

Why It Matters

For anyone building or investing in female sexual health, this paper is about the measuring stick. Three approved or investigational drug classes — testosterone, flibanserin, bremelanotide — were all evaluated against an endpoint that a growing body of clinical opinion says does not capture what the condition actually is. If baseline "satisfying sexual events" are substantially composed of obligation rather than desire, then an event-count endpoint may systematically understate a treatment that increases wanting without immediately changing frequency. That has direct commercial consequences: it shapes which molecules clear trials, which get reimbursed, and how sponsors price the risk of entering the category at all. It also lands squarely on the digital therapeutics and device side of the industry. Companies like Dare Bioscience, MysteryVibe and the digital-CBT platforms are all navigating the same endpoint question, often with fewer resources to argue with a regulator about it. Expect this paper to be cited in favor of desire-based and distress-based patient-reported outcomes over frequency counts. And there is a product-design implication that the market rarely says out loud: if a meaningful share of partnered sex among women with low desire is obligation-driven, then "more sex" is the wrong success metric for a sexual wellness product. Wanting is the metric. Very few products in this category are currently measured that way.

The finding comes out of a re-reading of baseline data across roughly a decade of randomized, placebo-controlled trials. Guptan and Simon examined four trials of a testosterone patch covering 2,204 naturally and surgically menopausal women, where baseline frequency clustered tightly at 2.5 to 2.9 satisfying sexual events per 28 days regardless of menopause type or concurrent hormone therapy. Four US flibanserin trials totaling 3,413 women produced a similar range of 2.0 to 3.0 events per 28 days. An unpublished 13-country European flibanserin trial with 915 participants averaged 2.41, though country-level variation was wide — from 4.19 events per month in the Czech Republic to 1.12 in Italy. Two bremelanotide trials covering over 1,200 women came in lower at about 1.2 events, which the authors attribute to a four-week placebo observation period built into those study designs. Age tracked inversely: a trial of naturally menopausal women averaging 55 reported the lowest baseline at 2.0, while premenopausal cohorts averaging 36 sat closer to 3.0.

The methodological problem this exposes is significant. When the FDA approved the first drug for premenopausal women with the condition in 2015, it required sponsors to measure success using criteria modeled on male erectile dysfunction trials — with heavy weight on the frequency of satisfying sexual events. But as the authors note, HSDD is fundamentally a cognitive condition, a deficit of mental desire, while ED is typically vascular or anatomical. Counting events to measure a psychological absence of wanting creates a mismatch, and the mercy-sex baseline is where that mismatch becomes visible: a woman with zero desire can log three events a month, leaving a drug very little headroom to demonstrate benefit on the endpoint regulators asked for.

Guptan and Simon offer a biopsychosocial framing for why the behavior persists, drawing on sexual selection research to argue that obligatory sex can function as a relationship-preservation strategy — a hypothesis they present as explanatory rather than established, and one that will draw legitimate methodological argument.

Sources

Update — 2026-08-28

{Initial entry — story first created.}