Not all fertility awareness campaigns work. Women can feel blamed or shamed, men remain 'over-optimistic'. Sophie Goodchild reports.
Public health campaigns encouraging men and women to protect their fertility can trigger a significant backlash - along with accusations of sexism.
Women in particular feel they are being blamed for their delay in starting a family or conversely that they are being pressured into having children, according to Lone Schmidt from the University of Copenhagen speaking in Barcelona.
"We see a consistent pattern in all countries," said Schmidt. "This backlash from women and women's organisations that public awareness campaign either shames or blames them for delaying childbearing. Our challenge is how we reach and engage people without getting into this conflict time after time."
This negative response to initiatives providing biological facts about fertility, such as declining egg numbers or sperm quality, is among half a dozen challenges identified by Schmidt that relate to awareness-raising.
Others include the role of the media, getting men on board, social inequality in fertility awareness, measuring the impact of a campaign and the global challenge around treating and preventing infertility.
Possible solutions suggested by Schmidt during her presentation include engagement worldwide to develop fertility campaigns and educational interventions. Tailored programmes are also needed to engage people from low educational backgrounds, she said, and schools could use sex education lessons to educate young men about infertility.
Fertility awareness includes people having an understanding of reproduction, fecundity, and related individual and non-individual risk factors such as sexually transmitted diseases and advancing age.
Men in particular have a poor awareness of fertility and many over-estimate the chance of pregnancy according to one systematic review of 43 studies highlighted by Schmidt, who said they tended to be "over optimistic".
Higher education is linked with an increased knowledge about fertility, and there is some evidence that fertility awareness increases with age.
Awareness-raising is carried out through fertility educational interventions, and campaigns such as the UK's Fertility Education Initiative and the Your Fertility project by the Victorian Assisted Reproductive Authority in Australia.
Studies show that interventions such as slide shows and oral information do increase awareness but any knowledge gained seems forgotten within six months. Others suggest that educating people about fertility can lower the age of childbearing, with some couples having a second child earlier.
Campaigns vary in approach such as awareness weeks or public service announcements. One carried out in Denmark in 2015 featured slogans like "Have you counted our eggs today?" and "Is your sperm swimming too slowly?".
Dr Schmidt said this campaign attracted "considerable backlash" from women, the media and politicians over the female part of the campaign. However, there was no reaction at all to the messages aimed at men.
In general, she said it was "impossible" to demonstrate that campaigns had any real effect, and that the focus should instead be on analysing their reach, for example among the general public.