While Western governments have long granted rights and assigned legal protections according to the supposedly objective criteria of chronological age, in practice, assessing age has been far more subjective — and the determination has always privileged some children while discriminating against others. Adult authorities often have used a functional age, filtered through categories of race, class, gender or ability, to make decisions about children and youths that are at odds with their chronological age — what scholars call a “double age.”
An example of how this played out was “age grading.” In the early 19th century, a child’s age took on new importance. In Northern cities, emerging public schools and orphanages began recording age as a measure of maturity or capacity; meanwhile, on Southern plantations and at slave markets, enslavers equated age with property value. Lacking information about children’s birth dates, adult authorities frequently assigned ages to children based on whether they looked or behaved according to a particular chronological age. Assigning an age to a child was important as Americans increasingly associated younger childhood with innocence and protection.
For example, in the late 19th century, the Women’s Christian Temperance Union led a national campaign to raise the age of consent, a history chronicled in a now-classic study. In 1885, most state laws had set the age of consent at a shockingly low 10 years old. (In Delaware, it was 7 years old.) By 1920, all but one state had raised it to 16. Age grading took shape across American society and became normative by the end of the 19th century.
In the early 20th century, psychiatrists invented the now-discredited notion of “mental age” to distinguish so-called “feebleminded” children from their “normal” peers. As a result, many children in schools and mental hospitals found themselves assigned a lower “mental age” than their chronological age. California’s institutions routinely assigned lower “mental ages” to ethnic Mexican children and adolescents on the basis of biased intelligence and psychological tests. This tactic allowed the state to exert greater power over individuals deemed younger than they actually were, often with tragic results — such as forced sterilization operations that disproportionately targeted women and girls of color. In California, for example, which carried out a third of all of the nation’s sterilizations between 1910 and 1960, eugenics leaders pioneered the use of sterilization in juvenile reform schools and mental hospitals, disproportionately targeting ethnic Mexican children and adolescents.