Hello, to lose weight you need to watch what you eat. Do not eat after 6-7pm because you won't be doing any physical activity that will make you burn calories. Do not eat at fast foods, avoid drinking soda(syrup and sugar) or drinking juice(high amount of sugar). Eat in portions don't eat until you feel full, just eat what you need. Eat when you feel hungry, not whenever you want, because you need to allow your body to consume what you have. Try to reduce carbs because they will turn into sugar which is bad for you.
Yes I think genetics plays a role on it, but you can always shape yourself into health food and good eating patterns, because if you know you come from a family that gains weight fast, you should know what not to eat, after reading around and following few tips and advice.
I hope this helps,