There are many myths and beliefs about twins and I cover about 70 of them in Twin Mythconceptions.

Over the years, 10 of these myths and beliefs have really stood out for reasons that are not fully understood. I have carefully researched every one of them with the aim of bringing clarity and reason to the fore. I see this as an important task, because the truth about twins will help twins, parents, educators and others understand so many crucial aspects of their unique situations.

My top ten myths and beliefs variously cover the extent to which twins run in families, characteristics of mothers and fathers who are likely to have twins, the special nature of twins’ communication with one another, selected biological features identical and fraternal twins and twins’ unusual prenatal circumstances.

1. Identical twins do not run in families. (False)
   • Identical twins do appear to run in some families—some populations in India, Jordan and elsewhere have unusually large numbers of identical twins within the same family.

2. Identical twins can communicate by extrasensory perception or ESP. (False)
   • There is no scientific evidence that twins exchange thoughts or ideas by reading each other’s minds—identical twins’ social closeness is better explained by studies showing that their common genes underlie their within-pair communication skills.

3. Your consumption of yams and other dietary choices increase the chances of conceiving twins. (True)

• It is thought that the white yam contains fertility-inducing properties that trick the female body into releasing hormones that promote ovulation–this may partly explain the high fraternal twinning rate among the Yorùbá of western Nigeria.

4. Older mothers are more likely to conceive fraternal twins than younger mothers. (True)
   • Women in their mid-thirties are more likely to conceive fraternal twins than younger mothers—releasing two eggs at the same time is not typical, possibly reflecting the aging process.

5. Identical twins always have one placenta. (False)
   • About one-third of identical twins have separate placentae.

6. Twins can look racially diverse. (True)

• Twin brothers and sisters born to couples of mixed racial or ethnic backgrounds sometimes inherit the different facial features or skin tones of one parent.

7. Twins are always born on the same day– or month or year. (False)

• Twins in the same pair can be born just before and just after midnight; on the last and first day of a given month; or on the last day and first day of consecutive years.

8. Male-female twins can be identical. (False)

• Twins of opposite-sex are fraternal because they do not share identical genes–males have an X and a Y chromosome and females have two X chromosomes, so we know that they originated from different fertilized eggs.

9. Identical twins have identical fingerprints. (False)
   • Identical twins do not have identical fingerprints–these features, which develop between the 10^th and 25^th gestational week, are affected by factors such as temperature, intrauterine position and density of amniotic fluid near the fingers.

10. Sharing a womb makes identical twins alike. (False)
    • The prenatal environment exposes identical twins to many different events, such as circulation and positioning–it is actually surprising that identical twins turn out as alike as they do.

We are pleased to over you a look at the book Twin Mythconceptions by offering you complementary downloads of a few of the book chapter that are all available here on ScienceDirect. To read the chapters below, simply click on the title.

• Twin Spouse and Unrelated Look-Alikes – This chapter examines the unusual family relations generated when twins marry twins or siblings, and even more unusual family relationships that emerge when they have children.

• Mind Readers? Twin Telepathy, Intelligence, and Elite Performance – This chapter tackles what is probably the most controversial and contentious topic of all when it comes to twins: extrasensory perception (ESP).

If you prefer to purchase a print or e-copy of the book, visit the Elsevier website. Apply discount code STC317 to save up to 30% off the list price and free global shipping.

Nancy L. Segal received a B.A. in psychology and literature from Boston University (1973), and an M.A. (1974) and Ph.D. (1982) in the Social Sciences and Behavioral Sciences from the University of Chicago. From 1982-1991 she was a post-doctoral fellow and research associate at the University of Minnesota, affiliated with the well-known Minnesota Study of Twins Reared Apart. She is currently Professor of Psychology at CSU Fullerton and Director of the Twin Studies Center, which she founded in 1991. Dr. Segal has authored over 200 scientific articles and book chapters, as well as several books on twins.

You can also read Dr. Segal’s other articles on twins below, and access her interview on “CBS Morning Show” about twin sisters separated at birth.

• Rare Twins Born to Parents of Different Ethnicity
• Do Twins Read Each Other’s Minds?
• Twin Spouses and Unrelated Look-Alikes