说的是同一件事情，也就是喝牛奶吃起司就会大大增加生双胞胎的可能性！这么高明的密方实在是不敢独享：）

　　文中也提到了多子丸，看来也是真的。只是可惜关于招式方面文中全然没有提及，暂时留下了一个谜。希望有兴趣的朋友能够身体力行，进行实践，然后把数据提供给文中的科学家，让他的研究更完满一些。哈哈哈哈！

May 20 (foodconsumer.org) - Women who eat lots of dairy foods such as milk and cheese are much more likely to have twins than those who eat plant foods, a new study has found.

Women who eat animal products, particularly dairy are five times more likely to have twins than women using vegan diet, found Gary Steinman, MD, PhD, author of the study and an attending physician at Long Island Jewish (LIJ) Medical Center in New Hyde Park, NY.

Besides being affected by diet, the study, published in the May 2006 issue of the Journal of Reproductive Medicine, has also found that the chance for a woman to have twins is influenced by heredity.

Dr Steinman is an obstetrician well known for his care of and research into multiple-birth pregnancies. In the study, he compared the rates of twin births among women who ate a regular diet, vegetarian diet with dairy, and vegan diet, which completely excludes animal products.

Women who ate meat and dairy are five times more likely to have twins than those who used a vegan diet. Steinman believes that high levels of insulin-like growth factor (IGF) in the meat eaters' blood are the culprit. IGF is 13 percent higher in the women who used animal foods than in vegan women, the study found.

IGF is a protein naturally released from the liver of animals -- including humans -- in response to growth hormone, circulates in the blood and makes its way into the animal's milk. In America, growth hormones are commonly injected in cows to boost milk and beef production.

Elevated levels of IGF in women caused either by consumption of meat and dairy products or by genetic influence increase the sensitivity of the ovaries to follicle stimulating hormone, thereby increasing ovulation and the odds of having twins.

The rate of twin births in the United States has increased by more than 75% between 1980 and 2003. While fertility treatment and intentional delay of childbearing contribute to the increase of multiple-birth pregnancies, researchers suspected that diet and heredity may also play a role.

"The continuing increase in the twinning rate into the 1990's, however, may also be a consequence of the introduction of growth-hormone treatment of cows to enhance their milk and beef production," said Dr. Steinman.

In cattle, regions of the genetic code that control the rate of twin births have been detected in close proximity to the IGF gene, indicating that genetics may affect the production of IGF.

Studies found some women are just genetically programmed to make more IGF than others. Rates of twin births in these demographic groups parallel the IGF levels.

Black women have highest IGF levels. They also have the highest rate of twin births. Asian women have the lowest levels of IGF and they have also the lowest twinning rate. Caucasian women fall in between in terms of their level of IGF and rate of twin births.

In agreement with the current findings, early studies have found that a woman's chance of having twins appears to correlate directly with her blood level of IGF.

"This study shows for the first time that the chance of having twins is affected by both heredity and environment, or in other words, by both nature and nurture," said Dr. Steinman.

"Because multiple gestations are more prone to complications such as premature delivery, congenital defects and pregnancy-induced hypertension in the mother than singleton pregnancies, the findings of this study suggest that women contemplating pregnancy might consider substituting meat and dairy products with other protein sources, especially in countries that allow growth hormone administration to cattle."

Editor's note: Some people comment that vegan women are least likely to have twins because they are malnourished. It sounds like having twins is indicative of having best nutrition. This is not necessarily true. Vegans can have a complete spectrum of nutrients as those who eat a regular diet if they can take care of their diet.