stevens/watkins ?

I have been tracing my ancestors which went by the last name of Watkins. Earliest known relative was Robert Watkins born 1754 Maryland. However, when DNA testing was done, my Watkins family matched many families with the last name of Stevens/Stephens/Stevenson. Matched only one other Watkins family. Looks like some Stevenswere from Stanford, CT. in 1600's. I believe this bunch then moved to Maryland. Bizarre case - illegitimate children ??? Any ideas out there ?