Yes, you are right. I meant handwriting error. Here is an example of the kind of error I find.
I can't attach the actual record, but for the toddler's death certificate, it lists his last name as Lee but both his parents are listed as Lees.
Name Samuel
LeeBirth Date abt 1870
Birth Place Phila
Death Date 9 Aug 1871
Death Place Philadelphia, Philadelphia, Pennsylvania
Age at Death 1 year 4 months 21 days
Burial Date 10 Aug 1871
Burial Place Philadelphia, Pennsylvania
Gender Male
Race White
Street Address back 634 South St
Cemetery Mount Moriah
Father James
LeesMother Jane
LeesFHL Film Number 2020944
This mistake happens all the time and makes it pretty challenging to search for records. I've also seen it written Lers and Lus. Ugh.
I've been searching for Elizabeth Jane

? just about everywhere. Pennsylvania, England, Scotland, Ireland. There is one record of a James Lees marrying an Elizabeth J Berk in 1858 in Pennsylvania, but I can't find any other record about her other than that. Any suggestions on how to find a woman's maiden name?