Hi Kirky
IGI is great research resource (specially as it is free!) but it is not 100%. It can often happen that you don't find something on IGI but will find it on Scotlands People. Are you looking at OPR entries (pre 1855)? I am assuming you are.
Even though you have found the children for the couple you are looking for, it may be that the OPR relating to their marriage/banns has been lost/destroyed over the years and you will not find any record for it.
All post 1855 BMDs will be on Scotlands People. IGI is particularly good in Scotland for the period between 1855-74, but again, you will find missing entries on it which are to be found on SP.
Regards.
Monica
