birth weight
Study: Fracking Linked to Low Birth Weight in Newborns
Study: Fracking Linked to Low Birth Weight in Newborns
Katarina Zimmer | Dec 15, 2017
Scientist find that living near a hydraulic fracturing site for gas and oil extraction could have adverse effects on infant health. 
Why Have Twins?
Jef Akst | Aug 11, 2011
Mothers more likely to have twins have heavier, healthier non-twin babies, possibly explaining why twinning evolved.