I have very skinny wrists, is this genetic or something else? how can i get rid of them?

Genetic: light boned, medium boned, or heavy boned usually run in families. Weight lifting puts much stress on your arms and wrists, and stimulates bone growth--that is likely the only way to make your wrists heavier. Be sure you have a normal vitamin D level, particularly if no one else is thin-boned in your family--you need a normal level to absorb dietary calcium.