Now this is a belief I have heard repeated a couple of times, and I wonder if there is any truth to it. I have heard that the way to tell apart boy and girl toddlers from the mid-19th Century (back when both would be dressed in off-the-shoulder dresses) is to look at the hairstyle; boys would have parts on the side, girls in the middle. Here is an example supposed boy and girl based on the hairstyle, both images from the 1850s.
Do we actually know if these hair parting 'rules' (side for boys middle for girls) were usually followed at this time? Is there another way to tell boys and girls apart in photos of this time? Are there subtle differences in the dresses that my eye is missing? Or were boys and girls at this time dressed and styled totally interchangably before age 3 or so.
Edit: I only mean in the United States.
It is true that there was not a hard and fast difference between boys' and girls' dresses at that age. It's not until they were about three to five that gender coding would start to distinguish boys' dresses as styled in a more masculine way, with few to no ruffles and a shorter skirt, sometimes styled more as a jacket and kilt or a long tunic and breeches. In contrast, girls of that age could be piled with frills; their fashionable jacket-like bodices would more resemble boleros, and their skirts would be slightly longer than boys'. Fashion periodicals of the era can refer to (for example) "dress for a girl of ten years", "dress for a child of two years" (bold mine), and "dress for a boy of five years" because a toddler's dress was not defined as a boy's or girl's.
The hair parting is very definitely true. Here is an example of a (boy and girl) labeled fashion plate from 1857; this boy from 1869; this boy from 1863; this boy from 1855. Compare to this girl of 1855; this girl of 1863. This rule wasn't invented for distinguishing children, though - it was followed by men and women overall. Women parted their hair dead center through nearly the entire century, while men parted theirs on the side.
American Victorian Costume in Early Photographs, by Priscilla Harris Dalrymple, shows a lot of photographs in which the more "masculine" child's dress corresponds to the side part, and often a "masculine" toy as well (not to mention a more boyish face).
