Birth to Two Years Old
Young children are sensual. They learn about themselves and the world through touch. They learn how to love through being touched.
Boys have erections from birth and girls lubricate from birth. By the age of one year most babies enjoy touching their genitals.
If a baby is reprimanded for or discouraged from touching their genitals they will start to feel there is something wrong with this part of them.
This is a good time to start naming the body parts. You can point to and name parts of your baby's body. By the time they are two most infants like pointing to and naming body parts.