Difference between Primary and Secondary Sex Characteristics in Boys and Girls

Primary sex characteristics mean the maturation of sex organs. It is directly related to reproduction. Primary sex characteristics occur due to the gonad stimulating hormone called gonadotrophin. 

The primary sex characteristics seen in boys and girls are:

Boys

• The testis and scrotum grow followed by growth of the penis

• The seminal vesicles, the prostrate and the bulbourithral gland enlarge and develop

• First ejaculation of seminal fluid occurs.

Girls

• Growth of the uterus, fallopian tube and vagina

• Ovaries produce ova and secrete hormones needed for pregnancy

• Menarche –beginning of menstruation.

Secondary Sex Characteristics

Secondary sex characteristic are the external changes that make them attractive to the opposite sex members. It is indirectly related to reproduction and they result from the action of growth hormone.

The secondary sex characteristics seen in boys and girls are:

Boys

• Growth of hair on face, arms, legs and shoulders and later on chest. Formation of pubic hair

• The skin becomes coarser and thicker and pores enlarge

• The fatty glands in the skin become active and produce an oily secretion

• The voice becomes deeper

• Adams apple enlarges

Girls

• Growth of body hair in the under arm and pubic region

• Skin becomes smooth and fine and produce an oily secretion

• Changed distribution in weight and fat

• More subcutaneous fat and fat deposits, mainly around the buttocks, thighs and hips

• Widening of hips

• Enlargement of breast