In fact I am not at all sure of the date of his birth or of his parents.
Jeannette will very probably be able to add more, but what I know for sure is:
a) that his wife and daughter (not him as far as I know) were buried together in Arnaboll in a grave which described them as 'Jane Sinclair, widow of Alexander MANSON M D Thurso, who died at Eriboll August 18th 1851 aged 76 years' and 'Jane Manson her daughter who died at Edinburgh July 2nd 1872 aged 63 years.'
b) that Alexander Manson and Jeanie Sinclair married in Thurso on 23 April 1799, when Jane (Jeanie) was about 20.
c) that they had (at least) four children in Thurso, Marion Macbeth in May 1800, Alexander in February 1801, Jane in April 1803 and Helen Sinclair in December 1805; these children and their mother/other relatives appear together in various censuses.
d) that Jane Sinclair was a widow when she died in 1851 and appeared without her husband in the 1841 and 1851 censuses, presumably because he had already died.
e) that an Alexander Manson was born in Thurso on 9 October 1774 to parents Alexander Manson and Margaret MacDonald; this couple also had children Christine in 1764, David in 1767, George in 1770 and Alexander in 1773.
And that's it. If my dob is right, Alexander would have been 24 when he married, which would be young for a doctor these days, but which seems reasonable for then. Certainly there is no obstacle that I know of to him having been rather older.
I would love to find a record of Alexander in practice or in his training. Obviously, finding his death/grave would be good too, but so far I haven't seen any of this.
As I say, Jeanette probably has more.
Alan