Wholemount photos of developing human fetal female internal genitalia staged by heel-toe measurements. Note (a) increase in size and morphological complexity with time, and (b) that it is impossible to distinguish the uterine corpus, cervix and vagina. Specimens photographed with transmitted light (9, 10, 11, 13 and 15 weeks) permit visualization of internal (epithelial) organization in regions not too thick. The 10-week specimen is shown at both low and high magnifications. Red arrowheads demarcate the epithelium defining the lumen of the uterine (Fallopian) tube. Green arrowheads define the epithelium lining the uterus. Relative sizes of specimens are not exact, but increase with age. From Robboy et al (2017) with permission.