I read through many pages of Appleby Magna, Leicestershire Parish records in the 18th centenary and I estimate about 10% of births seen in 1700's were described as bastard son or daughter or base born son or daughter etc.
By contrast I recently read many transcripts of Warwickshire parish records from early 1500s to mid 1600s and did not see any births / baptisms describing illegitimacy.
I should add I did see some instances of baptisms coming before parents got married But no judgemental comments were recorded in the parish records seen.
Therefore my question: Was the church more tolerant towards illegitimacy in the 16th and 17th centuries than in the 18th century. Or were illegitimate births not allowed to be recorded at all?
Could one explanation be that early baptism registers were short on detail?
Another is that fornication could be harshly punished in 16th and 17th centuries. This was a deterrent to illegitimacy.
This topic has been discussed before on RootsChat. Search for the words illegitimate, illegitimacy.
This thesis is specifically about East Yorkshire in 18th & 19th centuries but contains information about earlier times and England in general.
"The Incidence and Nature of Illegitimacy in East Yorkshire in 18th and 19th Centuries" by Margaret Sheila Oliver
https://hydra.hull.ac.uk/assets/hull:12306a/contentAppendices include:
Terms denoting illegitimacy in East Yorkshire parish registers.
List of tables includes:
Recorded illegitimate baptisms before and after 1753 Marriage Acts for selected East Yorkshire parishes.
List of figures includes:
Illegitimacy ratio for England 1538-1754
Rise of illegitimacy 1700-1839
Illegitimacy ratio for East Yorkshire 1538-1750
Comparison of illegitimate ratio England and East Yorkshire 1538-1750
Other studies are doubtless available.