What's maybe even more weird is that none of them bear more than a passing resemblance to one another.
First, the Bible versions:
And in the sixth month the angel Gabriel was sent from God unto a city of Galilee, named Nazareth, To a virgin espoused to a man whose name was Joseph, of the house of David; and the virgin's name was Mary. And the angel came in unto her, and said, Hail, thou that art highly favoured, the Lord is with thee: blessed art thou among women.
And when she saw him, she was troubled at his saying, and cast in her mind what manner of salutation this should be. And the angel said unto her, Fear not, Mary: for thou hast found favour with God. And, behold, thou shalt conceive in thy womb, and bring forth a son, and shalt call his name Jesus. He shall be great, and shall be called the Son of the Highest: and the Lord God shall give unto him the throne of his father David: And he shall reign over the house of Jacob for ever; and of his kingdom there shall be no end.
Then said Mary unto the angel, How shall this be, seeing I know not a man?
And the angel answered and said unto her, The Holy Ghost shall come upon thee, and the power of the Highest shall overshadow thee: therefore also that holy thing which shall be born of thee shall be called the Son of God. And, behold, thy cousin Elisabeth, she hath also conceived a son in her old age: and this is the sixth month with her, who was called barren. For with God nothing shall be impossible.
And Mary said, Behold the handmaid of the Lord; be it unto me according to thy word. And the angel departed from her.
And it came to pass in those days, that there went out a decree from Caesar Augustus that all the world should be taxed. (And this taxing was first made when Cyrenius was governor of Syria.) [i.e. 6-12 CE] And all went to be taxed, every one into his own city.
And Joseph also went up from Galilee, out of the city of Nazareth, into Judaea, unto the city of David, which is called Bethlehem; (because he was of the house and lineage of David:) To be taxed with Mary his espoused wife, being great with child.
And so it was, that, while they were there, the days were accomplished that she should be delivered. And she brought forth her firstborn son, and wrapped him in swaddling clothes, and laid him in a manger; because there was no room for them in the inn.
Now the birth of Jesus Christ was on this wise: When as his mother Mary was espoused to Joseph, before they came together, she was found with child of the Holy Ghost.
Then Joseph her husband, being a just man, and not willing to make her a public example, was minded to put her away privily. But while he thought on these things, behold, the angel of the Lord appeared unto him in a dream, saying, Joseph, thou son of David, fear not to take unto thee Mary thy wife: for that which is conceived in her is of the Holy Ghost. And she shall bring forth a son, and thou shalt call his name Jesus: for he shall save his people from their sins.
Now all this was done, that it might be fulfilled which was spoken of the Lord by the prophet, saying, Behold, a virgin shall be with child, and shall bring forth a son, and they shall call his name Emmanuel, which being interpreted is, God with us.
Then Joseph being raised from sleep did as the angel of the Lord had bidden him, and took unto him his wife: And knew her not till she had brought forth her firstborn son: and he called his name Jesus.
Now when Jesus was born in Bethlehem of Judaea in the days of Herod the king [i.e. 37-4 BCE], behold, there came wise men from the east to Jerusalem, Saying, Where is he that is born King of the Jews? for we have seen his star in the east, and are come to worship him.
And when they were departed, behold, the angel of the Lord appeareth to Joseph in a dream, saying, Arise, and take the young child and his mother, and flee into Egypt, and be thou there until I bring thee word: for Herod will seek the young child to destroy him.
When he arose, he took the young child and his mother by night, and departed into Egypt: And was there until the death of Herod: that it might be fulfilled which was spoken of the Lord by the prophet, saying, Out of Egypt have I called my son.
Then Herod, when he saw that he was mocked of the wise men, was exceeding wroth, and sent forth, and slew all the children that were in Bethlehem, and in all the coasts thereof, from two years old and under, according to the time which he had diligently inquired of the wise men.
So, in version 1, sometime between 6 and 12 CE, an angel tells Mary that she will become pregnant then later she and Joseph have to go the Bethlehem to be 'taxed; because one of Joseph's remote ancestors once lived there. It's not clear why it should be the town of this particular ancestor or how the authorities could possibly have checked that everyone had gone to the right town. Jesus is born and placed in a manger because there was no room at 'the inn', there only being the one, apparently.
In version 2, Joseph is embarrassed to find his fiancée Mary is pregnant even though they have not has sex. This would normally result in a stoning and the return of the dowry but Joseph plans to break the law and merely send her away. However, in a dream an angel tells him that this is nothing to worry about because God did it.
They are to call the baby Jesus because it is prophesied that they shall call his name Emmanuel, a name by which he is never known.
Moving swiftly on...
So Joseph marries Mary but doesn't have sex with her until after her baby is born. The baby is born in a house over which some wise men have seen a star, which somehow contrives not to be over any other house.
Then they have to run away to Egypt because all the babies under two are to be killed on the King's orders, so Joseph learns in another dream.
Mary's sister Elizabeth has a baby 6 months old which somehow escapes this slaughter too.
Well, that all seems perfectly clear.
Let's see how the Koran deals with this same story:
She [Mary] placed a screen (to screen herself) from them; then We sent to her our angel, and he appeared before her as a man in all respects.They obviously used a lot of brackets when they spoke in those days.
She said: "I seek refuge from thee to (God) Most Gracious: (come not near) if thou dost fear God."
He said: "Nay, I am only a messenger from thy Lord, (to announce) to thee the gift of a holy son."
She said: "How shall I have a son, seeing that no man has touched me, and I am not unchaste?"
He said: "So (it will be): Thy Lord saith, 'that is easy for Me: and (We wish) to appoint him as a Sign unto men and a Mercy from Us': It is a matter (so) decreed."
So she conceived him, and she retired with him to a remote place.
And the pains of childbirth drove her to the trunk of a palm-tree: She cried (in her anguish): "Ah! would that I had died before this! would that I had been a thing forgotten and out of sight!"
But (a voice) cried to her from beneath the (palm-tree): "Grieve not! for thy Lord hath provided a rivulet beneath thee;
"And shake towards thyself the trunk of the palm-tree: It will let fall fresh ripe dates upon thee.
"So eat and drink and cool (thine) eye. And if thou dost see any man, say, 'I have vowed a fast to (God) Most Gracious, and this day will I enter into not talk with any human being'"
(Koran 19: 17-26)
Quoted in: Werleman, CJ (2011-07-05). Koran Curious - a guide for infidels and believers (Kindle Locations 792-806).
Dangerous Little books. Kindle Edition.
Anyway, no mention of Joseph at all. Mary just gets told it's a done deal and goes off to a remote place where she gives birth under a palm tree. God thoughtfully provides her with a river to drink from and some dates to eat, provided she can shake the palm tree herself whilst in labour (can't have these women expecting to be waited on now, can we!), but tells her she is to tell any man who comes near her that she isn't going to talk to them.
Now, the curious thing about this, apart from how Mary was going to tell a man anything without talking to him, is that when this was related to the King of Abyssinia who had recently been converted to Christianity, he saw nothing wrong with it.
The background to this story is what was going on in Mecca at the time (around 620 CE). Some 200 Muslims had been sent by Muhammad to Abyssinia to keep them safe because the Quraysh (who were running the city) had imposed a trade boycott against all Muslims. Thinking Muhammad was building up his forces in Abyssinia, the Quraysh sent a delegation to see the newly-converted Christian king with a plan to tell him that Muslims were blaspheming against Jesus and to ask him to eliminate them.
It was Muhammed's cousin who recited the above verse from the Koran to the king to convince him that they respected Jesus and Mary - and it convinced him. He allowed them to stay and take refuge in his country.
Now, why would a new Christian convert in Abyssinia (modern Ethiopia) not see anything wrong with that tale of Jesus being born under a palm tree with no one in attendance and being fed on dates and watered by a miraculous river? Can you imagine a Christian despot in Medieval Europe being impressed enough with that to imagine that the teller was in full accord with Christianity?
A glance at the map might well hint at an answer.
Abyssinia (Ethiopia) lies just across the Red Sea from Saudi Arabia, near the so-called Horn of Africa, a little south of Mecca and a short sea-crossing from modern Yemen, then Sheba, where there were known to be both Christians and Jews, which were then more like different sects than distinct religions, and who traded north to Mecca and beyond and across to Africa. Muhammad is known to have had contact with Christians in Mecca who, along with Jews and local polytheist religions, all worshipped at the Kaaba and observed the rituals of Ramadan, which pre-date Islam by may centuries.
It is entirely possible that whatever version of Christianity Muhammad learned that story of the birth of Jesus from was the same version to which the King of Abyssinia had converted. This was a southern version which had migrated from Palestine down the Red Sea coast to Arabic Yemen and into Africa south of the navigable reaches of the Nile.
Meanwhile, further north in Palestine and up into Syria, Iraq, Asia Minor and West into the Roman Empire, other versions of the Jesus myth had been developed and promulgated by the different sects and traditions, by incorporating into it the myths of Persian and other gods then popular in the Roman Empire...
Clearly, all three of these versions of the birth of Jesus can't be right... but they can all be wrong.
I'll leave the Christians and Muslims to fight over who has the right version of the myth, just so long as they don't involve me in their fight.