Kentucky birth records pre 1800?

Hello Ms. Petruska,

Thank you for contacting the History Hub regarding your ancestors. Birth certificates are created by the state. The earliest birth records collected by Kentucky were 1852. Any earlier records were collected and kept by church or family members. You may consider contacting historical societies, the Daughters or Sons of the American Revolution, or state archives collections.

I hope this information is helpful. Best of luck with your research.

Jenette Parish

Perhaps this link would help: https://www.genealogyinc.com/kentucky/union-county/

Also check: https://www.familysearch.org/wiki/en/Kentucky,_United_States_Genealogy

Also the Kentucky Historical Society might have your info.  They may also be able to give you more specific sites.