I am 23 weeks pregnant, I have gained 11 lbs so far and have no stretch marks. My doctor told me they are genetic and my mom didnt have them; she also said if I didnt have any by 26 weeks I most likely would not get them. I couldn't care less if I get them or not, as long as I deliver a healthy baby and I am healthy, but am curious as to other womens experiences. I was about 118 lbs prepregnancy and still exercising daily. I cant wait for my little guy to arrive in early November!