MATCHED PAIR Studies of more than 14 million
sets of twins indicate that human traits, on average, are dictated equally by genes and environment.
In addition to knowing each
set of twins» genetic overlap (identical = more, fraternal = less), the researchers focused on individual
twins» reports
of marital satisfaction (a general measure
of the quality
of their marriages) and self - reported health that asks participants to
indicate their overall health, from «the worst possible» to «the best possible» health.