Here are a few fun facts about twins:

•  Up to 22% of twins are left-handed (only 10% of singletons are left-handed).
• Did you know that where you live could determine whether or not you conceive multiples? For example, if you live in Massachusetts and Connecticut, the twinning rate is 25% higher – but in Hawaii the rate of twin births is 30% less than the rest of the nation. In Nebraska and New Jersey the rate of triplets is double that of the rest of the nation.
• The Yoruba tribe in Nigeria has the highest incidence of twinning in the world. This is attributed to the large amount of yam/sweet potato they consume, which is thought to contain chemicals that stimulate hyperovulation. In fact, people of African American descent are more likely to have twins or multiple births. Conversely, people of Asian or Hispanic descent are less likely to have twins.
• Fraternal twins run in families. Identical twins are a completely random occurrence.
• There are seven types of twins.
• Due to the availability of sonograms earlier in pregnancy it is now estimated that for every live twin birth, there are at least six other ‘twins’ that no one knew about due to the vanishing twin phenomenon.
• Twins do not have to be born on the same dates. The longest gap between births is 85 days. This is called interval birth.
• 27 lbs, 12oz. is the heaviest combined birth weight of any set of twins.
• Only 14% of women carry multiples past 37 weeks. Most women give birth prematurely.
• Just over 50% of all twin births are spontaneous. Approximately 15% of triplet births are spontaneous and only 5% of quadruplet births are spontaneous.
• Twins do not have to have the same father. It is possible for a mother to release two eggs separately (as much as 24 days apart). Consequently, the twins could have different due dates.
• You have a 50% chance of having a c-section when you are pregnant with twins. You have a 100% chance of having a c-section if you are pregnant with more than two babies.
• Identical twins experience nearly identical brain wave patterns.
• Conjoined twins occur in every 1 out of 400,000 twin births.
• Once you’ve had fraternal twins, you are 3 to 4 times more likely to have another set (!)
• Women who have had four or more previous pregnancies are more likely to have twins.
• Women produce more ovulation-stimulating hormone as they age, increasing the chance of releasing more than one egg during ovulation. The chance of having twins rises to 4% between the ages of 30 and 34, and to 5% between the ages of 35 and 39.
• Having a maternal history of twins or other multiple births considerably increases your chance of becoming pregnant with twins.
• Women who are well nourished are more likely to have twin or multiple births.
• Twins are more common in large and tall women than in small women.