During which SMR stage is masculinization observed and the growth spurt occurs?

• A. Stage 2
• B. Stage 3
• C. Stage 5
• D. Stage 4

Answer: (D)

In boys, the rapid pubertal growth and visible masculinization come together as puberty moves into the mid-to-late stage, when testosterone drives both secondary sexual characteristics and a peak in height velocity. At this stage you’ll see clear virilization—facial hair, deeper voice, increased muscle mass—along with the fastest rate of growth, the pubertal growth spurt. That combination occurs in the stage where these masculine features are well established and growth is at its maximum, which is Stage four. Earlier stages show initial changes without full virilization or the peak growth, and later stages have maturation completed with no ongoing rapid height gain.