Human Bio Question

Factual Questions
1

I’m not good at biology at all, so this will probably sound stupid to most of you:

What controls us growing when we are young? A hormone of some form would be my guess. If so, would it be possible to manipulate that level to grow yourself to whatever size you wanted to be? And is it possible to selectively grow parts of your body (such as if you had ‘small’ feet in relation to the rest of your body). Also (and i doubt it), is it possible to reverse that hormone (or whatever it is), to shrink?

2

Human Growth Hormone (HGH) made by your pituitary gland. Years ago it came only from corpses’ glands, but today there’s a synthetic type. Google says that there are dangerous side effects, and that’s it’s used to treat dwarfism.