my parents played and bought music they liked.
if they didn't like it, they wouldn't buy it.

that's why I grew up listening to soul. that's what my parents listened to.

later on they tried to encourage me to like rap
and modern r&b singers, but it didn't take for the most part.

i guess my point is that kids are not discerning until they hit their teen years...
and if they are going to like music at all, they will like whatever you play for them.

so you can influence their taste just by playing good music around the house.