Children outside the womb develop abilities very similar to how their bodies develop inside the womb. First comes trunk strength and control, then arm, leg (crawling and walking) and head motor development followed by hand, feet, mouth and eye motor development.
Children have a hard time just skipping over these milestones. For instance, if a child does not have the trunk strength and control to sit up independently and they are constantly gripping their high chair for support, they are going to have a hard time developing the fine motor skills involved in feeding themselves (they don't have a free hand!).
Speech and sensory issues are also common in children with SB but with attentive parents and proper therapeutic and educational services many delays can be minimized if not overcome completely.