Hi. I'm 17 years old. I am 172 cm (5'8") tall, but very thin. My voice broke when I was 13 and I have adult facial, public and armpit hair. But my penis is less than 5 cm (2 inches) long, and I don't get erections. My testicles are small: left about 3.5 cm long (16ml?), right about 3cm (10ml?). Should I see a doctor? Or just wait?
Lewis (age 17)
It is not normal for a male who has secondary sexual characteristics (body hair and the like) not to get erections. You should have been plagued with spontaneous erections from shortly after you noticed you had pubic hair.
Yes, you should see a doctor. You also need to be completely honest with him. For instance, have you been using drugs? Anabolic steroids have a side effect of making a man lose the ability to have erections. As can selective serotonin reuptake inhibitors (SSRI), which are often given for ADD and ADHD, if the dosage level is too high.
Heavy bicycle riding can also cause problems if the seat isn't adjusted right (you don't want it holding your weight at the point between your scrotum and your anus).