An online definition of twins specifies two types, identical and fraternal. The Identical twins, always the same sex, result from the fertilization of a single egg by a single sperm, with the fertilized egg then splitting into two. Fraternal twins are fertilized by two separate sperm and the babies are no more alike than siblings born at separate times.
The small high school I attended in rural eastern Pennsylvania had five sets of twins, two identical and three that were fraternal. What was surprising was that the two sets of identical twins were from the same family. Teachers had a hard time telling the twins apart. I don’t know how my high school twins turned out, although I played on a baseball team with two of the sets.
Aside from the technical definitions of twins, there are many idioms for twins: carbon copy; spitting image; alter ego; like father, like son; two of a kind; all square; apples for apples; even stevens; and two peas in a pod. There are also many synonyms for twins: for example: duplicate, dual, parallel, counterpart, identical, couple, replica, matched, and similitude. Twins, where one is left-handed and the other right-handed, are referred to as “mirror” twins.
You can even have an “evil twin,” which might be your doppelganger or your second self. There is also a “vanishing twin syndrome,” when one of a set of twins disappears and a “twinless twin,” which refers to a person left alone after his/her twin dies.
Twin phonological words, which interest me as a linguist, also occur. Note: allowed/aloud; bean/been (although some English dialects pronounce them differently); ate/eight; brake/break; son/sun, and so on.
There are “twin cities” as well, such as Minneapolis and St. Paul in Minnesota in the US, and they sport a major league baseball team called, appropriately, “The Twins.” Are they sister cities or brother cities? They are several miles apart on opposite sides of the Mississippi River. Sometimes so-called twin cities are even on opposite sides of a national border, such as El Paso, Texas and Ciudad Juarez, Mexico.
Twins were subjected to terrible torture and research by the Nazis during the second world war and they have been favorites for experiments in our own culture. Consider the famous study of the “Botox twins,” in which one twin had Botox regularly over 13 years and the other did not. The one subject to Botox had fewer wrinkles and more youthful skin, allowing the company to make promotional claims about its products. However, there are now petitions to strengthen safety warnings about Botox and remove misleading claims from its cosmetic labeling.
Doctors and psychologists love to study twins. For example, the Handbook of Clinical Neurology (2010) states: “In a large twin study of over 11 000 twin pairs from Denmark, both the “no tension-type headache” and the “frequent tension-type headache” phenotype were shown to have a genetic component, whereas “infrequent tension-type headache” seemed primarily caused by environmental factors.”
The American Psychological Association justifies its studies of twins by claiming “because of what they can tell us about how our genes and environment interact to make us who we are.” One woman, Nancy Segal, who is professor of psychology at California State University, has authored approximately 200 scientific articles and book chapters, as well six books about twins and twin research. And such studies continue, to find out “who we are.”
What about twins in the Bible? Jacob and Esau are the most famous. They were the twin (fraternal) sons of Isaac and Rebekah (Genesis 25.21-26) and they grew up to be very different. Esau was an outdoor man, a skillful hunter, and the favorite of his father. Jacob was more of a homebody and his mother’s favorite.
When it came time for Isaac to bestow his blessings on his sons, Esau was born first and should have been the first (remember his identification mark?) to receive it. However, he had sold that right to Jacob for some red stew. Both went on the become the “father of nations,” although they had conflict over land and possessions. In Hebrews 12.15-17l Esau’s birthright is used as an example of ungodliness because he put a physical desire over a spiritual blessing.
Another set of twins mentioned in the Bible is probably an unwanted set, named Perez and Zerah (Genesis 38.28-30), whose mother was Tamar and whose father was Judah. Judah thought that Tamar was a prostitute and solicited her services, so the twins had a father with questionable behavior. He is also mentioned in the NT in the genealogy of Jesus (Matthew 1.3) but that is all.
Was Thomas Didymus (which means “twin” in Aramaic) a twin or was he so called because he had twice as many doubts as the other disciples?
Some brothers, cousins, or even friends, function like they are as “close as twins,” and that is a positive attribute.
Jesus may not be my twin, but he is my “brother” and my best “friend.”
Karl Franklin