Alright let's list all the differences in society if the baby born started off stronger than the parent it was born from.
-No more military kids and sex trafficking with kids, they'd be too risky and next to impossible to control.
-More respect for children especially from teachers
-Schools probably would have far less children
-Parents would be scared to have children because some super baby would boss them around as opposed to them bossing around the kid.
-There'd be a lot more homocides of toddlers on parents, especially in the primitive countries where most parents do not have access to firearms.
-There'd be a lot more inheritances
-If said toddler was also just as smart as an adult there'd be a power imbalance between toddlers and adults. You'd have a scenario just like in that Kids Next Door tv show.
*The baby/toddler would need to be small yet have incredibly dense muscles like a bear or gorilla OR he'd have to be born some other way through giant artificial wombs or motherfucking portal magic OR pregnant humans would look like kiwi birds.
-Pedophillia laws would probably not be as frowned upon and we'd even get adultphillia to be illegal.
-If the power imbalance is too high then civilized countries would create kid pens and specialized babysitter to domesticate the children. Which obviously wouldn't work because there'd be too many. Third world countries would be ruled by children.
-Children on children wars as the dominant age.