Can drinking milk increase your chances of conceiving twins? Yes—if your milk comes from cows given rBST (recombinant bovine somatotropin), also referred to as rBGH (recombinant bovine growth hormone). A recent study published in The Journal of Reproductive Medicine reports that vegan women who exclude dairy products from their diets have a twinning rate one-fifth that of women who consume conventional cow's milk (2006, vol. 51, no. 5). Why? The hormone rBST is converted to IGF (insulinlike growth hormone) in the cow's liver and then passed on through its milk. IGF increases ovulation in humans and thus the rate of dizygotic (fraternal) twins. Where rBST is banned, such as in the United Kingdom, twinning rates are significantly lower.