by Dr. Caroline Moreau, Johns Hopkins University Professor and WHGI Research Director
Before the Data Begin
International Youth Day is a good moment to ask a question global health data still struggle to answer: what is happening in girls' lives before the age at which we start counting them?
Most major population-based surveys of sexual and reproductive health (SRH) begin at 15. There are good reasons for that: first sex, early marriage, and first births become visible during later adolescence, and asking younger adolescents about sexuality raises real ethical and methodological challenges.
But development does not wait until 15. Between 10 and 14, girls are already learning what changes in their bodies mean, what they can expect from relationships, whether they can say no, and whom they can turn to for help.
Those years remain largely missing from the population-level data used to guide adolescent health programs, and they are the years in which the attitudes and expectations that shape later sexual and reproductive health take hold.
What If We Started Measuring Earlier?
Researchers from Addis Ababa University and faculty from the William H. Gates Sr. Institute for Population and Reproductive Health (WHGI) set out to test whether measurement could start earlier.
Building on the Global Early Adolescent Study (GEAS) and the PMA Ethiopia platform, Dr. Zimmerman and her team developed a survey for girls aged 9 to 14 and piloted it with 300 girls in Addis Ababa, Afar and South Ethiopia, including urban, rural, and pastoralist settings.
Rather than asking younger girls the questions put to older adolescents, it focused on what develops before sexual activity: knowledge about puberty and reproduction, gender attitudes, communication, consent, and coping.
What the Data Reveal About Early Adolescence
The survey itself proved workable. Girls and caregivers accepted it across all three settings, including more conservative communities.
The difficulties were just as revealing. Girls in rural and pastoralist communities were sometimes reluctant to discuss puberty because it could signal readiness for marriage. Girls living as domestic workers in their employers’ households found that questions about caregivers and social networks did not always fit their lives. These are partly problems of survey design. They are also findings about girls’ lives.
Ideas about Sexuality Take Shape Early
The pilot also shows how much is already taking shape between ages 12 and 14. Only 8% had ever been romantically involved, yet nearly 80% said they would feel guilty about romantic attraction, and 65% about sexual feelings. Ideas about sexuality were already taking shape well before romantic experience was common.
What Girls Know—and Feel Comfortable Discussing Varies
The same pattern appeared in what girls felt able to discuss and what they knew. Just over half had ever talked with someone about menstruation, compared with 29% about pregnancy and 25% about sexual relations.
Knowledge was uneven: two-thirds knew that pills or injectables can prevent pregnancy, but only 47% knew condoms protect against HIV, while 28% believed HIV could be passed on through kissing.
Half worried that seeking contraception would make others see them as promiscuous.
Communication Makes a Difference
Communication also seemed to matter. Girls who had talked about menstruation or pregnancy tended to know more about pregnancy, and those who had discussed menstruation reported less worry about their own bodies and development. Gender attitudes, by contrast, were not closely linked to the other competencies measured.
Why Earlier Data Matter
Together, these findings show that long before sexual experience becomes common, girls are already developing the knowledge, expectations, and social pressures that will shape what comes next.
Girls’ lives do not begin at 15. Our evidence should not either.
