11. In males, what is the first noticeable change during puberty? A) muscles become larger B) testicles increase in size C) voice deepens D) sperm production begins 12. Because adrenarche occurs about two years earlier than gonadarche, increased sexual attraction and subtle changes in secondary sex characteristics begin happening much earlier than people think—around ________ years of age in both males and females. A) 4 B) 5 C) 7 D) 11 13. Sexual maturation for human males typically proceeds in a certain manner. Which of the following typically occurs last (i.e., Stage 5)? A) Sperm production begins. B) Hormone production begins. C) Scrotum becomes darker in color. D) Growth of facial and chest hair begins. 14. In females, what is the first noticeable change during puberty? A) Breasts begin to enlarge. B) Pubic hair appears. C) Hips enlarge. D) First menstruation occurs. 15. ____________ involves the HPG axis and leads to the development of primary and secondary sex characteristics. A) Menarche B) Gonadarche C) Adrenarche D) Pubarche 16. _____________ occurs before gonadarche and results in the development of secondary sex characteristics and increased sexual attraction. A) Adrenarche B) Delayed phase preference C) Binge drinking D) Chlamydia 17. Increased sexual attraction and subtle changes in secondary sex characteristics occur at approximately what age? A) 7 years B) 9 years C) 11 years D) 13 years 18. What is the average age at menarche in the United States today? A) 10 years B) 12 years C) 14 years D) 16 years 19. Which ethnic group tends to start menstruation earlier than other ethnicities? A) Hispanic B) Asian American C) non-Hispanic white D) African American 20. The average age at menarche has ________ since the 1920s. A) decreased B) increased slightly C) increased drastically D) stayed the same