Stretch mark is what we call striae gravidarum, occurs as part of physiological change of the body to pregnancy. In regards to whether genetic plays a role, it's kinda hard to say. But studies found that when mother has stretch marks during her pregnancy, then her daughter might have it during her pregnancy. Ultimately, stretch mark is due to mechanical stretching which results in the rupture of the fibres in the dermis. It could also be due to increased hormone glucocorticoid in the body.

As to how to reduce it, trofolastin cream applied daily plays a significant role.

not sure about that.

As I said, genetic might play a role. But till date it is inconclusive. There might be a lot of articles out there, depending on what u wanna believe and whether it's trustworthy or reliable or not. I'm just laying the facts from evidence based medicine.