[Tanniker Smith]

I've heard competing theories from people of differing denominations, that say, basically

Joseph had other sons before Mary (he was older, after all)

Joseph and Mary had other children after Jesus, the "usual" way

Or, Jesus was an only child and Mary was "ever Virgin".

[Mr. K]

If it was important to know, The Bible would probably tell.

EVERYTHING ELSE is just waste of time speculation.

Isn’t there something important these people could be doing?

[ctdonath2]

Then there’s the widespread theory that Mary is “perpetually virgin”, even though she had others by Joseph. This [deranged view] also opens the possibility that the aforementioned Nun is correct insofar as “perpetual virgin” would not preclude Mary copulating before having Jesus.

Reducto ad absurdum.