Let's take an in-depth look at the Scottish birth records. Births prior to 1855 are recorded in the Old Parish Registers (OPRs) as Baptisms. These are fairly scant entries, often limited to the name of the child, the name of the father, the date of the baptism and perhaps the names of the witnesses. In some instances, depending on the minister, the date of birth might also be recorded, or the name of the mother might be listed, but these details are not a guarantee. It is for this reason, that it is often difficult to ensure you have the right family when researching back prior to the civil registration.
From 1855, we get the registration of the birth. This, being a statutory record, has more detailed information as well as standardized information across the country. From the birth registration, we get date, place and time of birth of the baby, the names of both parents, with mother being listed under her maiden name and then the date and place of marriage of the parents.
Proving legitimacy of the child fell to the mother. She proved this by sending or taking the father to the registrar's office to register the birth. This is shown in the column regarding the informant where it will state "father, present" This is verifying that the father was present at the registrar's office and claimed paternity of the child. If father was away at the time - war, at sea, etc, then the marriage record would suffice. Any child whose father was not present at the registrar's office would be deemed illegitimate. If the parents subsequently married, the birth was legitimized under Scots law. But that information still had to get to the registrar. Once it did, there will be writing in the margin of the birth register noting new information, and this alerts you to the fact that there is a Record of Corrected Entry (RCE) to view.
The exception to a birth being legitimized upon marriage of the parents, however, was if one of the parents was already married at the time of the baby's birth. In this case, since the parent was not legally free to marry, even a subsequent marriage of the two parents would not legitimize the birth.
Both OPR Baptisms and Statutory Birth Registrations are available on the ScotlandsPeople website.
References to illegitimacy and naming of the potential father often appear in the Kirk Session records for the parish in which the mother and baby lived. These are digitized and will be added to the ScotlandsPeople website in 2017. Until then, the records are at the National Records of Scotland in Edinburgh.
If mother took the father to court for child support, the case will show up in the Sheriff Court records for the council or burgh in which the mother lived.