title: Is there a viability-vulnerability tradeoff? Sex differences in fetal programming.
abstract: OBJECTIVE
  In this paper we evaluate the evidence for sex differences in fetal programming within the context of the proposed viability-vulnerability tradeoff.
  
  
  METHODS
  We briefly review the literature on the factors contributing to primary and secondary sex ratios. Sex differences in fetal programming are assessed by summarizing previously published sex difference findings from our group (6 studies) and also new analyses of previously published findings in which sex differences were not reported (6 studies).
  
  
  RESULTS
  The review and reanalysis of studies from our group are consistent with the overwhelming evidence of increasing risk for viability among males exposed to environmental adversity early in life. New evidence reported here support the argument that females, despite their adaptive agility, also are influenced by exposure to early adversity. Two primary conclusions are (i) female fetal exposure to psychobiological stress selectively influences fear/anxiety, and (ii) the effects of female fetal exposure to stress persist into preadolescence. These persisting effects are reflected in increased levels of anxiety, impaired executive function and neurological markers associated with these behaviors.
  
  
  CONCLUSIONS
  A tacit assumption is that females, with their adaptive flexibility early in gestation, escape the consequences of early life exposure to adversity. We argue that the consequences of male exposure to early adversity threaten their viability, effectively culling the weak and the frail and creating a surviving cohort of the fittest. Females adjust to early adversity with a variety of strategies, but their escape from the risk of early mortality and morbidity has a price of increased vulnerability expressed later in development.
authors.affiliation: Women and Children's Health and Well-being Project, Department of Psychiatry & Human Behavior, University of California, Irvine, United States. Electronic address: casandma@uci.edu.
authors.forename: Curt A
authors.initials: CA
authors.lastname: Sandman
authors.forename: Laura M
authors.initials: LM
authors.lastname: Glynn
authors.forename: Elysia Poggi
authors.initials: EP
authors.lastname: Davis
mesh_terms: D000223:Adaptation, Psychological; D001007:Anxiety / Q000378:metabolism / Q000523:psychology; D015415:Biomarkers / Q000097:blood; D001921:Brain / Q000002:abnormalities*; D002648:Child; D002657:Child Development; D003346:Corticotropin-Releasing Hormone / Q000097:blood / Q000378:metabolism; D056344:Executive Function; D005239:Fear; D005260:Female; D047109:Fetal Development; D005328:Fetal Viability; D005865:Gestational Age; D006801:Humans; D006854:Hydrocortisone / Q000097:blood / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism; D008297:Male; D008895:Milk, Human / Q000378:metabolism; D009929:Organ Size; D010913:Pituitary-Adrenal System / Q000378:metabolism; D010920:Placenta / Q000378:metabolism; D011237:Predictive Value of Tests; D011247:Pregnancy; D037841:Pregnant People / Q000523:psychology; D011297:Prenatal Exposure Delayed Effects / Q000378:metabolism / Q000523:psychology; D011446:Prospective Studies; D011597:Psychomotor Performance; D012727:Sex Characteristics; D013315:Stress, Psychological / Q000523:psychology*
chemical_list: D015415:Biomarkers; D003346:Corticotropin-Releasing Hormone; D006854:Hydrocortisone
keywords: Child development; Fetal behavior; Fetal programming; HPA axis; Prenatal stress; Sex differences