In rodents, AGD is measured from the anus to the posterior base of the genital tubercle (Gallavan et al., 1999 ). In contrast to rodents, the external genitalia are well developed at birth in humans with the genital tubercle transformed into the penis in males and clitoris in females. Investigators have used different landmarks to measure AGD in humans to replicate the measurement in rodents. In males, AGD has been measured from the anus to the perineoscrotal junction (anoscrotal distance) (Salazar-Martinez et al., 2004 (link)), to the posterior base or to the anterior base of the penis (Hsieh et al., 2008 ) (Fig.1). Measurements in females use the distance from the anus to the anterior fourchette (anofourchettal distance) (Salazar-Martinez et al., 2004 (link)) or to the base of the clitoris (anoclitoral distance) (Liu et al., 2014 (link)). The method described by Salazar-Martinez et al. is commonly used; it is more reliable and has a lower inter-observer variability (Dean and Sharpe, 2013 (link); Papadopoulou et al., 2013 (link); Salazar-Martinez et al., 2004 (link)). In this review, the term AGD describes ‘anoscrotal distance’ in males and ‘anofourchettal distance’ in females unless otherwise stated (Salazar-Martinez et al., 2004 (link)). Although AGD has been widely used as a marker of potential endocrine disruption in utero, its limitations include a lack of standardisation of methodology and information on reproducibility (Table-1) and insufficient data on normative references, including ethnic differences (Dean and Sharpe, 2013 (link)). AGD is associated with birth weight to a varying degree depending on the population studied (regression coefficient adjusted for gestation ranges from 1.5 to 3.0 mm/kg) (Papadopoulou et al., 2013 (link); Romano-Riquer et al., 2007 ; Salazar-Martinez et al., 2004 (link)) and there is no consensus for adjusting AGD for the variations in body size. In addition, low birth weight is itself a risk factor for TDS as it is associated with hypospadias, cryptorchidism, male infertility and TGCC (Francois et al., 1997 (link); Juul et al., 2014 (link); Michos et al., 2007 (link); Toppari et al., 2010 (link)).