Q states that no one in the continuum procreate, and he even argues with another Q about how to do this. However, in Star Trek: The Next Generation's True Q (1992), he states that two Q took the form of humans and procreated (resulting in Amanda, the Q he is testing on the ship). So obviously, he's quite aware of how to go about procreating.
When Q is trying to convince Captain Janeway to have a child with him, he asks her if she'd like to have one someday. In Threshold (1996) she had 3 children (nonhumanoid) with Lieutenant Paris. She said she would like to have a child. When in fact she has already had 3.
When Tuvok, Harry, Chakotay and Tom engage in the firefight at the Q Continuum to rescue the Captain, Tim Russ is sporting his regular human ears instead of his Vulcan ones.
Q tells Janeway that no pair of Q had ever mated and/or procreate; but, way back in True Q (1992) he searched for a young woman who was the offspring of two Q members who had gone native on Earth.
The "Grey" Q wears the collar rank insignia (3 Stars, no wreath) of a Confederate Colonel (equal to a Starfleet Captain) but the sleeve rank of a lieutenant. Q wears the rank of an Army Captain (equal to a Starfleet lieutenant).