Human studies in genomic imprinting, a process causing genes to be expressed according to parental origin, can be limited by tissue availability, tissue-specific expression and cellular heterogeneity. This work shows that umbilical cord overcomes many of these limitations, having robust imprinted gene expression and appropriate methylation patterns. Expression of the PHLDA2 and PEG10 genes in cords of Asian Chinese full-term babies were significantly different in low birth weight (<2.5 kg) babies.  Associated changes in PEG10 promoter methylation implicates expression and methyation of this imprinted gene in compromised fetal growth, pointing to the potential of imprinted genes as fetal growth biomarkers. (By Dr. Anne Ferguson-Smith, http://jmg.bmj.com/content/early/2012/10/04/jmedgenet-2012-100858 )