You don't say which parish John Thomson Stewart was born in, but if he was illegitimate it's possible that the Kirk Session minutes of whichever parish it was might have reported the case.
The surviving KS records are at www.scotlandspeople.gov.uk in the Virtual Volumes section.
Ha! That would be useful wouldn’t it.
Thomsons are from Rashgill in Dumfries but close to the Tinwald border. Stewarts are in the same area or pop up in Tinwald and Closeburn.
JST or JTS is listed in the census as born Dumfries. Given the tightness of his birth year it wouldn’t take much to go through Kirk Sessions - good shout. The cost would need a trip to the centre though. He’d be in the KS for Tinwald for his parochial school board position- maybe.
SP have been great and sent the right image for the William Stewart born to James S and Agnes T and it does say “lawful son” given how hot they were on this stuff I have to work on the assumption they were married. It matches with James’ occupation (mason) to JST/JTS’s death cert.
I might see if James Stewart appears in criminal/asylum/emigration records. My gut feels like this is an abandonment - no reason to call yourself unwed if you are widowed unless a scandal or something.