I have a question about both my my kids. Myson is 10 now but when he was a baby and even a toddler…

I have a question about both my my kids. Myson is 10 now but when he was a baby and even a toddler he was never curious about his body and still isn't really. Not like I've heard that babies especially little boys would be like as a toddler. Now my almost 19 month old is. And other peoples it seems. Why is that?? Should my son be curious? Is my daughter just a head of the game...? Sorry for asking such a question but I just don't know. My parents didn't talk to me about ANYTHING concerning our bodies. Don't know if I should at this age with my son since he's 10 but also idk but he doesn't seem like he's interested or cares and don't know if it's normal fory 19 month old at this age. I don't even know if this is an appropriate place to ask. Lol....