Where did they marry? the marriage certificate, depending on the country, may show birthdates & placesm parents' names, etc.
Scottish vital records (births, marriages, deaths) are available from Scotland's People website but there is there is a 100 year cut off point for viewing the actual certificate so, depending on exact date of birth, you may have to order his certificate (which will list date and place of parents' marriage).
Once you get the parents' names you might be able fo find them in the 1911 Scottish census (from same site) and trace the family further back if you wish.
