Harvard medical researcher Eliot Porter took this photo of his son Jonathan enjoying some tummy time in 1938, the year he had his first exhibition at Alfred Stieglitz's 291 Gallery in New York. In 1939, he decided to become a photographer full time. This print was made in the 1950s.
And thus history shows us, it's not exploiting your kids for marketable content that's the problem, it's doing it well. Bloggers and sponsored Insta moms, take note.