Study questionWhat are the views of men from Greece, Nepal, and the UK on having children and what is their knowledge of fertility?Summary answerBetween countries, there were similarities and differences in men’s views to having children. Men showed limited fertility knowledge, and access to fertility information varied.What is known alreadyThe global total fertility rate (TFR) has dropped to below 2.5 compared to 5 in 1950, currently being 1.61 in the EU. Internationally, the age at which people are having children has increased and is over 30 in many countries. Delaying parenthood is leaving many with smaller family sizes than desired or involuntary childlessness due to age-related infertility.Although many men are keen to be fathers, existing studies relating to fertility knowledge and having children focus heavily on women. Compared to women, men’s fertility knowledge is limited as fertility education is rarely taught or tailored for men.Study design, size, durationTwo anonymous surveys were conducted. The UK survey (live from 25 April – 1 December 2021) was launched via social media. Men internationally could complete the survey, and high numbers of men from Nepal participated.The Greek survey (live from 11 – 26 May 2021) was launched in Greece through a market research company. The end sample size was n = 244 for Greece, n = 205 for Nepal and n = 128 for the UK.Participants/materials, setting, methodsMen aged 25 to 45 years old, who wanted children but were currently childless, were included. There were four parts to the survey: basic demographics; their attitude to having a family; their fertility concerns; and their fertility knowledge. For the UK survey, since one of the authors had a link with Nepal, particular effort was made to recruit from Nepal as well as from the UK.Main results and the role of chanceWhen asked how many children men wanted, most Greek (59%), Nepalese (66%) and UK (58%) men wanted two children, but higher levels of Greek (24%) and UK (25%) men wanted three children compared to Nepalese men (9%)(p < 0.001).The ideal age men wanted to have had/have their first child was 35 years in Greece (23%), but it was 30 years in Nepal (24%) and in the UK (30%). The COVID-19 pandemic had not affected most men’s decision to have children: Greece’s (64%), Nepal (48%), UK (70%). But it had affected 21% Greek, 27% Nepalese and 16% UK men who are now intending to delay having children.Greek (46%), Nepalese (48%) and UK (47%) men felt moderately informed on female fertility. Greek (45%), Nepalese (50%) and UK (45%) men felt more informed about male than female fertility. When questioned on when they think a woman is fertile in her menstrual cycle, 50% Greek, 38% Nepalese, and 42% UK men answered incorrectly.The internet was the most common source men accessed fertility information from: Greece (67%), Nepal (30%) and the UK (26%). The second most common source for Greece (18%) was doctors, but for Nepalese (18%) and UK (18%) men, it was school.Limitations, reasons for cautionThe study had a relatively small sample size (n = 577). It is well documented that men typically do not show high engagement with surveys. It was only promoted on social media. Respondents were typically highly educated, active on social media and knew English or Greek to an adequate level.Wider implications of the findingsThe International Fertility Education Initiative is developing resources to deliver tailored fertility education across different populations. This survey shows that there are cultural differences that need to be considered when designing such resources.Trial registration numberNot applicable