Fig. 2. Serial section reconstruction of embryonic (E17-E20) male and female urethral UGT. The urethral epithelium (UrE) is shown in blue, SM originating from the urethra (UrSM) and bladder (BLSM) is shown in magenta, and the VMP is shown in pink. At E20, in the male, a prostatic bud emerging from the urethra is shown in yellow. Comparison of male with female shows a discontinuity between the urethral SM and the bladder SM. The VMP aligns with the SM discontinuity. In both males and females the SM is discontinuous from E17 to E19. At E20, in females the SM layer has become continuous, while in males it remains discontinuous.