The study design was a cross-sectional online survey implemented in the survey software Typeform v2 ( The study was online from . Subjects were told that the survey was about the qualities of their ideal partner(s). Participants younger than 18 were not able to participate in the survey. All participants completed a 14-item section focusing on demographic information and long-term preferences. In a third part, participants could answer questions about potential short-term partners, if they were willing to do so. Ten parallel language versions of the survey were developed: Chinese, Danish, English, French, German, Italian, Footnote 3 Japanese, Portuguese, Russian, and Spanish. Translators were native speakers of their respective languages who were contracted by the menstrual cycle tracking app Clue on a regular basis. A “four eyes” approach (one translator and one proofreader per language) was used. The survey was advertised via email campaigns to the respective user bases, messages within the Clue app, and social media channels. Continua a leggere