The larger horse hips of the female Centaurs allow a dramatically longer gestation time, maybe as much as 18 months. The human part would be dramatically more developed. Overall that might make centaurs more likely to evolve superhuman intelligence.

This is very funny but my brain went straight to: babies are only so under developed because evolution has done us dirty so far with the human hips, if the centaur mother can pass the horse part obviously the human part can be more fully developed

Lol thank you for this.