Fascinating Things We've Learned from Twin Studies

Scientists studied twins.They studied twins in utero.They noticed twins started reaching out as early as 14 weeks into pregnancy. They began caressing each other, touching mouths and eyes. Scientists conclude social behavior emerges before birth.

There isn't enough data for this claim. However, Thomas Bouchard's 1979 study onThomas Bouchard's 1979 study on twins separated at birthincludes a fascinating anecdoteabout names. Male twins separated at birth and reunited at age 39 found they both married women named Linda; both divorced, then both married women named Betty. One named his son James Allan, the other named his son James Alan. They also both had pet dogs named Toy.Male twins separated at birth reunited at age 39 found they both married women named Linda; both divorced, then both married women named Betty. One named his son James Allan; the other named his son James Alan. Both had pet dogs named Toy.

Twin boysBruce and Brian Reimerdid not consent to participate in a case studyon genderTheir parents volunteered them. After an accident during circumcision, Bruce suffered genital injuries. Dr. John Money, who believed upbringing determined gender, suggested Bruce's parents raise him as a girl.

When scientists compared personality traits of twins raised together versus those raised apart, they found twins raised apart had more similar personalities.more similarthan expected. Researchers concluded personality traits come mostly from genetics. Traits strongly linked to heredity include leadership and obedience to authority.

A viral video of twin babies speaking gibberish shows a common occurrence. One study estimated about 40 percent of twins invent their own languages.own languages.This practice helps them apply meaning to sounds. The made-up language usually fades as children's real language vocabularies grow.

These findings may shift how we view prior results. We cannot ignore that our environment affects genes. Identical twins do not have identical DNA. DNA makeup can change via epigenetics. DNA modification starts in the womb and continues lifelong. This explains why identical twins become more different as they age.do notactually have identical DNA. DNA makeup can change via epigenetics. DNA modification starts in the womb and continues lifelong. This explains why identical twins become more different as they age.differentas they age.

Twin studies teach us that IQ is genetically determined.IQis genetically determined. Genes also affect how much enjoyment a child gets from learning and how motivated they are to succeed in school. Twin studies show that62 percentof individual differences in academic achievement result from genetics.

People generally do not choose to be gay. However, twin studies provide the scientific evidence.scientific evidenceResearchers reviewed twin studies in 2001. They found identical twins show a higher likelihood of sharing the same sexual orientation than fraternal twins.

Scientists studied identical and fraternal twins. They concluded about one-third of the variation in happiness comes from genetics.Genetics can account for some of the difference in happiness between people. Scientists looked at a gene that moves serotonin, a chemical that lowers stress hormones. Genetics set happiness, but other factors may also play a part.Scientists focused on a single gene that helps transport serotonin, a neurotransmitter that reduces stress hormones. This gene determines happiness, but other factors mix with it.

Twin studies show genes significantly affect whether people are religious.Genes affect religiousness.Twins raised apart show strong similarities in faith or lack of faith. Researchers found 40 to 50 percent of religiousness is set by genes.

Researchers asked identical and fraternal twins about drinking and hangovers. They asked about experiences with drinking and hangovers.Genes determine how bad hangovers are.Identical twins showed much more similar chances of getting hangovers than fraternal twins.

Popular belief says eating disorders stem from culture alone. A recent twin study suggests a strong genetic part exists.A recent twin study suggests a genetic component in eating disorders.Researchers measured female twins' internalization of the thin ideal—how much they accept social pressure to be thin. Identical twins' scores were more similar, suggesting genes make people more susceptible to eating disorders.

One part of that story has scientific backing: If one identical twin divorces, the other twin is also more likely to divorce than fraternal twins.If one identical twin divorces, the other twin faces a higher chance of divorce compared to fraternal twins.If your marriage ends, it might not be your fault. You could have just been born with bad genes.