Hi Marcie,

1871:
Address: 49 Duke Street, South LeithWilliam Laidlaw, m, head, 29, cab driver, b. Leith
Margaret Laidlaw, f, wife, 25, -, b. Edinburgh
John Laidlaw, m, son, 2, -, b. Edinburgh
1881:
Address: 3 Laurie Street, South LeithWilliam Laidlaw, m, head, 36, cab man, b. Leith
Margaret Laidlaw, f, wife, 33, -, b. Edinburgh
John Laidlaw, m, son, 12, baker's message boy, b. Edinburgh
1891:
Address: 38 Duke Street, South LeithWilliam Laidlaw, m, head, 48, cab - hirer, b. Leith
Margaret Laidlaw, f, wife, 44, -, b. Edinburgh
John Laidlaw, m, son, 22, cab - hirer, b. Edinburgh
1901?:
Address: Hill Street Cancer Hospital, GlasgowJohn Laidlaw, m, patient, 36, formerly coachman (domestic), b. Leith
Marriage:
William LAIDLAW and Margaret LAING, 1863, Leith
Children (extracted from IGI):
Charles William LAIDLAW, 1863, Leith (mother Margaret Ann LAING)
I cannot find a birth for John to these parents so it would be interesting to find where you found his birth certificate. It looks like he could have been registered under another name and brought up as William and Margaret as their own.
hume