One of the unusual Messianic predictions is that something strange would occur around the conception and birth of Messiah.
Isaiah 7:14
"Therefore the Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel."
I am almost certain that the word "virgin" in Hebrew.... means young unmarried woman......
I am a Christian who believes that the Ruach ha Kodesh, the Holy Spirit.... overshadowed Mary the Mother of Rabbi Yeshua - Jesus and told her.......
to go and sleep with her espoused husband Joseph... so that Yeshua - Jesus and his identical twin older brother Judas Didymus Thomas would be born at the correct time..........
The Holy Spirit is claiming authority over exactly how to interpret the Sabbath law..... by healing through Rabbi Yeshua - Jesus on the Sabbath and.....
the Holy Spirit/ Ruach ha Kodesh is claiming authority over marriage......
because many people do not have the luxury to obey the exceptionally strict Essene rules on marriage that Mary and Joseph were attempting to obey.... until the Holy Spirit intervened.
The presence of nothing unusual about the conception of Simon Bar Kochba should have been a major sign to Rabbi Akiva... that Simon Bar Kochba could not be the Moshiach.
The alternative theory on the conception timing for Yeshua and Thomas is explained here around page 60 or so:
The Thomas Book