ALEXANDER TSIARAS / SCIENCE PHOTO LIBRARY. ALEXANDER TSIARAS / SCIENCE PHOTO LIBRARY.
Endoscopic image of the human foetus in vivo, after 9 weeks, showing the genitals. Sexual differentiation is not apparent until the 18th or 19th week, and the organ seen (known as an indifferent phallus) could still form either the penis or clitoris. The endoscope, a series of lenses and a fibre-optic light source, is inserted through the cervix (the neck of the womb) and manipulated until a "window" into the amniotic sac is found (ie an area where the wall is thinner).
Model release not required. Property release not required.