Leptin has been identified as a possible gene for the acquisition of these thrifty traits. On a larger anatomic scale, the molecular mechanisms are broadly caused by a suboptimal environment in the reproductive tract or maternal physiological adaptations to pregnancy. See also Evolutionary developmental psychology Evolutionary physiology Phenotypic plasticity Trivers–Willard hypothesis Thrifty gene hypothesis Prenatal nutrition and birth weight References External links British Medical Journal Topic Collections: Barker Hypothesis Diabetes Obesity Biological processes