Strictly speaking, every science fiction tale presents its own version of future and therefore there are as many science fiction universes as there are science fiction stories. Many SF tales follow dictates of a particular subgenre like Cyberpunk or Space Opera of which, see the separate entry.
... male, as a passage for sperm.
The external urethral sphincter is the skeletal muscle that allows voluntary control over urination.
In the human female, the urethra is ...