Biblical Unitarians argue that Isaiah 7:14 in Hebrew (almah) refers to a young woman of childbearing age, not necessarily a perpetual virgin. The term almah is distinct from bethulah (virgin), and the Septuagint's choice of parthenon (virgin) represents a Hellenistic interpretive tradition. In the original historical context of Isaiah 8th-century Judean politics, the sign was addressed to King Ahaz regarding his immediate circumstances, not as a remote messianic prophecy.

Biblical Unitarians hold that while the early Christian community applied Isaiah 7:14 to Jesus's miraculous birth narratives, this represents theological reinterpretation rather than original prophetic intent. Jesus's birth from Mary (whether virginal or not) is not the foundation of his divine nature in their understanding, since they deny his pre-existence and deity. The 'sign' in Isaiah's context was a promise to Judah during the Syro-Ephraimite crisis, not necessarily about the Messiah centuries later.