After reading almost the entire Psychology 1001 book, the chapter still highlighted in my mind is Human Development, especially regarding childhood development. Coming from a large extended family and being an older relative, I was the professional babysitter for all my younger cousins.
At first this responsibility was met with hesitation. Should a one-year-old be walking without help? How old do babies really need to be to eat certain snacks? If they're crying, should I just let them cry themselves to sleep? But even if I didn't know every specific rule, who wouldn't want to get paid $20 for an hour amount of work?
Exploring the factors of motor development, social development, Piaget's and Vygotsky's theories helped cement in my head a clearer picture of childhood development. Although Piaget's and Vygotsky's theories have pros and cons, they lay out a developmental stage of learning and thought processes. As someday hoping to be a mother, the factors of motor and social development helped me understand the more biological side of childhood development.
So as you all go on to have families in the next 10-20 years maybe you should double-check the criteria of your babysitter. Even if it is only one night a week, do you trust your children to someone who doesn't even know around what age babies start to walk?