Fascinating Things We've Learned from Twin Studies  

Katherine Ripley
3k votes 826 voters 77k views 13 items

List Rules Vote up the most fascinating things twin studies have taught us

About 3 out of every 100 births in the United States yields twins. Studying twins is a way for scientists to determine how much of our characteristics are influenced by genetics, since identical twins share nearly 100 percent of their DNA, whereas fraternal twins or normal siblings only share about 50 percent. This list is full of the most interesting twin study findings, and you might be surprised by how significant a role genetics play in determining your future.

These interesting twin studies also give us insight into how human beings interact with one another. Vote for what you think is the coolest twin study discovery.
Social Behavior Starts in the Womb
Social Behavior Starts in the ... is listed (or ranked) 1 on the list Fascinating Things We've Learned from Twin Studies
Photo: Wikimedia Commons
Scientists who have studied twins in utero have noticed that they started to reach out to each other as early as 14 weeks into the pregnancy. They begin to caress each other and touch each other's mouths and eyes. Scientists say these observations lead to the conclusion that social behavior can emerge even before birth.
Is this fascinating?
Twins Often Invent Their Own Language
Ranker Video
Video: YouTube
That viral video of twin babies speaking gibberish to each other actually depicts quite a common occurrence. One study estimated that about 40 percent of twins invent their own languages. This is their way of practicing applying meaning to sounds. The made-up language usually fades as the children's real language vocabularies expand.
Is this fascinating?
Most Personality Traits Are Inherited
Most Personality Traits Are In... is listed (or ranked) 3 on the list Fascinating Things We've Learned from Twin Studies
Photo:  Gianne Karla Tolentino/via Pexels
When scientists compared the personality traits of twins who were raised together against those who were raised apart, they found that the personalities of twins who were raised apart were more similar than they expected. The researchers concluded that personality traits are mostly determined by genetics. Interestingly, the traits most strongly determined by heredity are leadership and obedience to authority.
Is this fascinating?
Gender Identity Is Genetically Determined
Gender Identity Is Genetically... is listed (or ranked) 4 on the list Fascinating Things We've Learned from Twin Studies
Photo:  Bessi/Pixabay/CC0 1.0

Twin boys Bruce and Brian Reimer didn't consent to participating in a case study on gender. Their parents volunteered them, after an accident during what should have been a simple circumcision left Bruce with significant injuries to his genitals. Dr. John Money, who believed that gender was entirely determined by upbringing, suggested that Bruce's parents raise him as a girl.

The parents took the doctor's advice, and Bruce became Brenda. The experiment seemed to go just as Dr. Money planned, until Brenda became a teenager. She became depressed and then suicidal. To save her, her parents told her that she had been born a boy, and from that point on, she decided to live life as a man.
Is this fascinating?