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Ten Things You've Always Wondered About Twins

Interesting Questions and Facts About Twins


Updated May 16, 2014

Twins are fascinating. They've been the subject of myth and mystery and a source of curiosity to many. Even those who know twins or have them in the family may have some questions about them. Have you ever wondered what causes twins or whether they have their own language? Explore the mysteries with these ten things that you've always wondered about twins.

1. Do Twins Have the Same Fingerprints?

Photo reprinted with permission of Arie Shalem.
Twins have a lot in common. Identical twins even share the same DNA, for the most part. But does that include fingerprints?

2. Can a Boy and a Girl be Identical Twins?

Photo reprinted with permission of Suzanne.
Every parent of twins faces the question. "Are your twins identical or fraternal?" The general public doesn't really understand exactly what the terms mean; if they did, they wouldn't ask whether a set of boy/girl twins are identical!

3. Can Twins Read Each Other's Minds?

Photo reprinted with permission of Irene Parnitke.
One of the magical mysteries associated with multiples is that they share a special connection beyond that of ordinary siblings. You'll often see them start to say the same thing at the same time. While the twin bond is a special aspect of their unique relationship, is it really endowed with extraordinary supernatural qualities? Do they share the same thoughts -- or read each other's minds?

4. Can There be a Hidden Twin?

twin ultrasound pictureseven week
© 2008 Pamela Prindle Fierro, licensed to About.com, Inc.
Every pregnant woman has a passing thought that perhaps there is more than one baby in there. Before ultrasound technology allowed a sneak peek inside the womb, twins were often a surprise to their parents. Despite the clarity of new technology, I receive emails every day from readers who suspect they are having twins, even when an ultrasound image only shows one baby. Are they right?

5. Do Twins Have Their Own Language?

Photo reprinted with permission of Raf.
When my twins were toddlers, I'd observe them passing toys back and forth. As they'd accept the toy from the other, they'd respond "Aachee." Eventually, my husband and I adopted the term, and it became a family way of saying, "Thank you." Was it an example of twin talk? Or just baby babble?

6. If Identical Twins Have the Same DNA, Why Aren't They Exactly Alike?

Photo reprinted with permission of Cesca.
Anyone who knows a set of identical twins knows that they are alike in many ways, but also very unique individuals. Why is that? Identical twins form from a single egg/sperm combination and share the same genes. While they often look very similar and have the same tastes and interests, they're also very different. Find out why identical twins are different, and how twin research is giving scientists important insight into human genetics.

7. Can Twins Have Different Birthdays?

Photo reprinted with permission of Kyra.
Twins, by definition, are two offspring born together, right? Yet, some twins blow out their candles on different days. Sometimes they celebrate their birthdays weeks or months apart, and in some cases, in different years!

8. Do Twins Run in Families?

Photo reprinted with permission of Four Healy Twins.
Everyone knows someone who is a twin or has a twin. And there's a general assumption that twins run in families. Some families do seem to have clusters of multiples in their family tree. Is it coincidence? Or a genetic trait?

9. Can Twins Have Different Fathers?

Photo reprinted with permission of Nicole.
By definition, twins have the same mother. But, have you ever wondered if twins could have different fathers? Don't tell me you're not curious about this!

10. What Causes Identical Twinning?

Photo reprinted with permission of Kim Samples.
There are many known factors that increase the chances of fraternal multiples. In recent years, the multiple birth rate has risen dramatically and the increase has been attributed to many reasons, including fertility treatments, hormones in dairy products, and mothers who delay childbearing until they are older. Yet, the rate of identical twinning has remained steady, about 3 in 1,000 births. Identical -- or monozygotic -- twins form when a single zygote (egg/sperm combination) splits into two. Why would it do that?

11. Bonus! One More Thing You've Always Wondered...

I often hear the claim ... twins skip a generation. What does that mean? That if you are a twin, you won't have twins? If you've ever wondered whether this is true, find out the facts.

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