Always asking the physician is a great idea this is infact true!
It's part of the brain stem,
They all coincide with each other although they are each individually important exercise and your diet are connected,you can't have too much food and run a marathon without cramping. Too much stress will have an effect on the consistency of your diet and your diet on your exercise, now heredity is a whole other realm, you cannot control that or change it. But if you are so worried about your heredity then you should seek counseling with a mentor or a paid counselor because that will affect all of your overall health.
Having body fat contributes to having a menstrual cycle. If a woman loses too much body fat, she can stop having her menstrual cycle because you need a certain amount for it to be able to function as normal. I don't think the body would benefit from ceasing to menstruate, because at that point it isn't really healthy. However, usually if a woman gains back some of the body fat or starts eating fattier foots/exercising less, her period will start again.