Consider Weight
Women with a BMI of 30 or more (who are obese) have more chances of conceiving twins as compared to women with a normal BMI. This might sound like an ironic statement from me because obese women have difficulty conceiving.
But my theory is, extra fat leads to high levels of estrogen. The high levels of estrogen in the body lead to overstimulation of the woman’s ovaries. So, instead of releasing one egg only, the ovaries might release two or even three during the ovulation period. 
Marry a woman with good height
Women who are taller than an average woman are most likely to have twins. One study, backed by science reveals that women who are 5’ 4.8” in height are more likely to have twins rather than women that are 5’ 3.7” in height.
The reason is quite unclear, even for the doctors. However, one theory is that better nutrition, which is also responsible for good height increases the chances of having twins. So, if you are a man longing for twins, you should look for tall women.
Age Matters
Women who are over 30 have more chances of conceiving twins. The FSH hormone rises when a woman gets older. The FSH hormone is a follicle-stimulating element that is responsible for egg development in the ovaries before they are released for the male egg in the ovulation period.
The eggs require more follicle stimulation to grow in older women as compared to younger women. This is why the body produces higher levels of FSH hormone. Sometimes, the FSH hormone reacts with the follicles and releases two eggs from the ovaries instead of one.
