Andrea - (fe)male name

Solution 1:

My strong suspicion is that Andrew came into use outside the Greek language almost entirely as a product of Christianization (as this is the name of one of the twelve disciples of Jesus) which would have penetrated Southern Germany around the 3rd or 4th century of the common era, and would have reached Northern Germany several centuries later. The translation of the Bible into a Germanic language was into Gothic in the 4th century CE, was made from the Greek version, and this apparently was a precedent for translation conventions in all subsequent editions, most of which were not made until the late Middle Ages. Until the Protestant Reformation and Luther's famous German bible translation, however, most Germanic Christians would have used a Latin mass and bible accessible verbatim only to the clergy.

Andrea was probably adopted as a female form of Andrew at some time after the original Greek meaning was lost, which probably would have been almost immediately in Germanic languages, as the Biblical context would not have conveyed the underlying Greek meaning.

The relevant Wikipedia article provides the Biblical context that is the origin of the name but doesn't clarify the answer to your exact question.

Andrea is a male name in Italian and Albanian, and may have become a female name in Germanic languages because the ending sounds feminine in those languages. (Similarly, while the Italian job title "barista" sounds feminine in English, it is actually unisex in Italian.)