Final answer:
Sex hormones emitted by the gonads create secondary sex characteristics. In males, testosterone leads to traits like facial hair and deeper voices, while in females, estradiol and progesterone result in breast development and fat distribution.
Step-by-step explanation:
Sex hormones, secreted by the gonads (which are the ovaries in females and the testes in males), are responsible for secondary sex characteristics. In males, the primary sex hormones or androgens, primarily testosterone and androstenedione, lead to the development of features such as facial hair, deepening of the voice, and increased muscle strength. In females, the hormones estradiol and progesterone, secreted by the ovaries, are responsible for characteristics including the development of breasts and the distribution of body fat in the hips, buttocks, and thighs. Both males and females produce these hormones, but they do so in different amounts.