not developed all the way

[notfullydeveloped]

hi everyone im a 17 year old boy. i hit puberty when i was 14. at first i grew pubic hair. it took about a year for that to grow. then when i was 15 my voice changed and got deep. it took a few months for the voice to change. then i got about 4 inches taller and gained some weight. also my penis and testicles increased a little but not a whole lot. from 16 to 17 i had no further growth. im 17 years old now and i have no armpit hair, no leg hair, no facial hair. and my penis is only 4.5 erect. whats wrong with me it seems like i stopped going through puberty. im not finished. i can ejaculate but very little sperm. im about 5'7'' 150 pounds.

[Deanna L Aftab Guy, MD]

Puberty signals start via the pituitary which starts with subtle signals to the brain via a hormone called LH or leutinizing hormone. This is secreted in pulses in a pattern that when it is mature signals to the gonads to produce testosterone (in boys) and estrogen in girls.
The androgens that the adrenals make are not directed by LH, they are produced in a rather unknown way but are typically starting around age 6 or even 7 with a minimal effect, these androgens-NOT testosterone will cause the secondary characteristics that you talk about concerning hair and body odor.
The size of the genitalia is influenced by testosterone and that is in turn affected by the LH hormone.
So ultimately as I suggested, start with your pediatrician or internist or family doctor to see if you need an evaluation or not. You sound like a few other social things are stressing you besides a significant endocrine problem and starting with your physician will help you keep sane.

[notfullydeveloped]

what exactly causes puberty. like what makes the penis grow. i heard that its just testosterone that causes all the changes. u think maybe i have low testosterone.

[Deanna L Aftab Guy, MD]

You describe a history alot like a late bloomer in regards to adrenal function kicking in at 14, the hair and body odor are from adrenal male hormones, not from the testes. Once the brain starts signalling in a mature fashion that is when testicular development becomes appropriate to make pubertal levels of testosterone, demonstrating enlargement of the genitalia and increased male pattern muscle mass. Being 17 and having only started to have things kick in 3 years ago it is very likely you will still develop, the axillary hair and leg hair are not necessarily puberty but rather genetic and cultural. Many Asian and American Indian descendants have little or no chest or arm hair but develop completely normally pubertal wise.
So height-well a bone age will answer alot for you, I would start with your doc, your impression of your development may be different from their's on exam, if they want to see if you are done growing a bone age can see how old your growth plates are and if they are not quite 16 or so you still have room to grow and may indeed be a late bloomer or what is called constitutional delay, your height may be normal based on genetics and if puberty kicked in late but was abrupt your growth plates may be fused.
I would check with your pediatrician or internist and ask for an overall assessment, there may be another concern like low thyroid that developed, slowing things after they finally started, or other problem. Or it may just be reassuring that you are just fine.