Does the Virgin Birth have Pagan Origins? Part II

~
There are plenty of sources from the second and third century in which the early writers created, critiqued, and debated the virgin birth myth.

Even the Catholic Encyclopedia admits this: http://www.newadvent.org/cathen/15448a.htm

"The opponents of the historical actuality of the virgin birth grant that either the Evangelists or the interpolators of the Gospels borrowed their material from an early Christian tradition, but they endeavour to show that this tradition has no solid historical foundation. About A.D. 153 St. Justin (Apol., I, xxi) told his pagan readers that the virgin birth of Jesus Christ ought not to seem incredible to them, since many of the most esteemed pagan writers spoke of a number of sons of Zeus. About A.D. 178 the Platonic philosopher Celsus ridiculed the virgin birth of Christ, comparing it with the Greek myths of Danae, Melanippe, and Antiope; Origen (c. Cels. I, xxxvii) answered that Celsus wrote more like a buffoon than a philosopher. But modern theologians again derive the virgin birth of Our Lord from unhistorical sources, though their theories do not agree.

The Pagan Origin

Theory A first class of writers have recourse to pagan mythology in order to account for the early Christian tradition concerning the virgin birth of Jesus. Usener [30] argues that the early Gentile Christians must have attributed to Christ what their pagan ancestors had attributed to their pagan heroes; hence the Divine sonship of Christ is a product of the religious thought of Gentile Christians. Hillmann [31] and Holtzmann [32] agree substantially with Usener's theory. Conrady [33] found in the Virgin Mary a Christian imitation of the Egyptian goddess Isis, the mother of Horus; but Holtzmann [34] declares that he cannot follow this "daring construction without a feeling of fear and dizziness", and Usener [35] is afraid that his friend Conrady moves on a precipitous track. Soltau [36] tries to transfer the supernatural origin of Augustus to Jesus, but Lobstein [37] fears that Soltau's attempt may throw discredit on science itself, and Kreyher [38] refutes the theory more at length.