Here are some examples of what researchers have discovered through studies of MATR twins:

  • Some pregnancy complications, such as hypertension, nausea and toxemia, are genetically determined.
  • Among those with epilepsy, genetic factors determine the cause and duration of seizures.
  • Genetic factors account for more than half of the variation in obesity in both adult men and women.
  • The number of loving and supportive relationships an individual has is substantially influenced by that individual's temperament, which in turn is shaped partly by genes.
  • Identical twin children are more alike for attention-deficit hyperactivity disorder, conduct problems and drug abuse than non-identical twins, suggesting that these behaviors are influenced genetically.
  • Children do not "learn" alcoholism from their parents the way they learn their political or religious beliefs. The children of individuals with alcohol problems are themselves at increased risk for such problems because of the genes they inherit.
  • Genes appear to influence depression in girls after the onset of puberty.
  • Genetic factors account for the stability of blood pressure from early to late adolescence.
  • The perception by adolescents that religion is important to them strongly inhibits behavior problems, including substance abuse and association with antisocial peers.