How much were you paid in your last job? http://ampland.fun/ ampland Researchers compared three studies for this latest research. The Christchurch Health and Development Study (CHDS), which includes biological and adopted children; the Early Growth and Development Study (EGDS), an adoption-at-birth study; and the Cardiff IVF (In Vitro Fertilization) Study (C-IVF), an adoption-at-conception study within genetically related families and genetically unrelated families.