title: Beware of the weaker sex: don't get too close to your twin brother.
authors.affiliation: Division of Neonatal and Developmental Medicine, Department of Pediatrics, Stanford University School of Medicine, 750 Welch Rd, Suite 315, Palo Alto, CA 94306, USA. dstevenson@stanford.edu
authors.forename: David K
authors.initials: DK
authors.lastname: Stevenson
authors.forename: Jon E
authors.initials: JE
authors.lastname: Tyson
mesh_terms: D001724:Birth Weight; D015986:Confounding Factors, Epidemiologic; D003627:Data Interpretation, Statistical; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D012107:Research Design; D012737:Sex Factors; D014427:Twins