The claim is utterly false.
Egyptian mythology is not a single, monolithic source. The legends differed from time to time and region to region. But there is a very consistent treatment of this particular point in Egyptian mythology.
This post contains graphic language and visually graphic Egyptian artwork about this particular claim. Both the language and the artwork are necessary to demonstrate the claim as invalid. However some readers may not wish to go further in this post.
The Bible’s teaching about the Virgin Birth of Christ has these basic components:
2. The mother, while inheriting human nature and a sinful nature from Adam, was not engaged in any actions in violation of the 6th Commandment. In other words, Mary was not fornicating or sleeping around.
3. The conception of her Son was accomplished by God declaring His will through His angel, without any sexual action on her part or on the part of any other human or spirit.
“Mighty Isis who protected her brother,Who sought him without wearying.Who roamed the land lamenting,Not resting till she found him,Who made a shade with her plumage,Created breat with her wings.Who jubilated, joined her brother,Raised the weary one’s inertness,Received the seed, bore the heir,Raised the child in solitude,His abode unknown.
[“The Great Hymn to Osiris” on the Stela of Amenmose, Louvre C 286
Lictheim, Miriam, Ancient Egyptian Literature, Vol. II: The New Kingdom, University of California Press, Berkely, 1976, p. 83]
The text with the picture states:
Abb. 5: Das bemalte Kalksteinrelief aus dem Totentempel Sethos’ I. in Abydos (1280 v.Chr.) zeigt den toten Osiris auf einer Bahre. Auf seinem erigierten Phallus empfängt Isis als Falkenweibchen postum den Rächer und Erben des Osiris, Horus. In menschlicher Gestalt hält Isis rechts ihre Hände schützend über den toten Bruder. Links wohnt Horus mit Falkenkopf seiner eigenen Erzeugung bei.
Fig. 5: ( 1280 BC) The painted limestone relief from the mortuary temple of Seti I at Abydos shows the dead Osiris on a stretcher. On his erect phallus is Isis, as falcon female, she posthumously receives Horus, the avenger and heir of Osiris. In human form Isis is holding her hands protectively right over the dead brother. On the left stands Horus with his falcon’s head involved with his own production.[“Sterben, Tod Und Totenwelt Im Alten Israel/Palästina.” Accessed December 23, 2014. http://www.unibe.ch/unipressarchiv/heft118/beitrag05.html.]
Even in Wallis Budge’s translation “Legend of the Birth of Horus, Son of Isis and Osiris” we find the same lack of virgin birth:
|Budge: Legends, pl. 14|
15. She flew round and round over this earth uttering wailing cries of grief, and she did not alight on the ground until she had found him. She made light [to come forth] from her feathers, she made air to come into being by means of her two wings, and she cried out the death cries for her brother. 16. She made to rise up the helpless members of him whose heart was at rest, she drew from him his essence, and she made therefrom an heir. She suckled the child in solitariness and none knew where his. place was, and he grew in strength. His hand is mighty (or, victorious) within the house 17 of Keb, and the Company of the Gods rejoice greatly at the coming of Horus, the son of Osiris, whose heart is firmly stablished, the triumphant one, the son of Isis, the flesh and bone of Osiris.
[Budge, Wallis. “Legends of the Gods, The Egyptian Texts: Introduction: Summary: V. Legend of the Birth of Horus, Son of Isis and Osiris.” p. 105.
Accessed December 23, 2014. http://www.sacred-texts.com/egy/leg/leg08.htm.]
The traditional result of Osiris’s dismemberment is that there are many so‑called tombs of Osiris in Egypt; for Isis held a funeral for each part when she had found it. Others deny this and assert that she caused effigies of him to be made and these she distributed among the several cities, pretending that she was giving them his body, in order that he might receive divine honours in a greater number of cities, band also that, if Typhon should succeed in overpowering Horus, he might despair of ever finding p47the true tomb when so many were pointed out to him, all of them called the tomb of Osiris.Of the parts of Osiris’s body the only one which Isis did not find was the male member, for the reason that this had been at once tossed into the river, and the lepidotus, the sea-bream, and the pike had fed upon it; and it is from these very fishes the Egyptians are most scrupulous in abstaining. But Isis made a replica of the member to take its place, and consecrated the phallus, in honour of which the Egyptians even at the present day celebrate a festival. [emphasis mine] [Isis and Osiris by Plutarch published in Vol. V of the Loeb Classical Library edition, 193, p. 358]