Which is more likely: That the whole natural order is suspended or that a Jewish minx should tell a lie? ~David Hume
Now, feel free to be offended by my rather forward question, but don’t pretend as if you’ve never wondered whether or not Jesus was the illegitimate son of a lying adulteress. So, given your internal admission, how do we attempt to answer this seemingly salacious yet sensible question? The short answer is, we can’t. Aside from the irrational and unhistorical religious tales contained in both the official and unofficial corpus of early Christian texts, we have virtually nothing to help us answer any question about the alleged historicity of Jesus.
In the words of the atheist bible scholar who believes in a historical human Jesus, Bart Ehrman:
What do Greek and Roman sources have to say about Jesus? Or to make the question more pointed: if Jesus lived and died in the first century (death around 30 CE), what do the Greek and Roman sources from his own day through the end of the century (say, the year 100) have to say about him? The answer is breathtaking. They have absolutely nothing to say about him. He is never discussed, challenged, attacked, maligned, or talked about in any way in any surviving pagan source of the period. There are no birth records, accounts of his trial and death, reflections on his significance, or disputes about his teachings. In fact, his name is never mentioned once in any pagan source. And we have a lot of Greek and Roman sources from the period: religious scholars, historians, philosophers, poets, natural scientists; we have thousands of private letters; we have inscriptions placed on buildings in public places. In no first-century Greek or Roman (pagan) source is Jesus mentioned. 
So then, if such is the case, let us give both the rational historicists (people who believe Jesus was a legendary mortal) and Christian apologists (people who believe that phantoms fornicate with Jewish virgins) the benefit of the doubt, but not so much benefit that we wander down the yellow brick road of faith-induced insanity. Let us, as rationally-minded investigators, retain a modicum of common sense and concede from the outset, that tribal deities don’t impregnate virgins, as was believed to be the case with Zeus and Alcmene, as well as many others from our dark and superstitious past. But in the spirit of fairness, let us employ a more tempered yet similar style of circumstantial speculation to attempt an answer to this ultimately vacuous question. For if such speculation can form the sandy foundations of a worldwide faith, it should certainly be capable of accommodating our somewhat facetious investigation.
When Monty Python’s ‘Life of Brian’ first hit cinemas in 1979, and in the years to follow, it caused an almost unprecedented uproar amongst Christians of all stripes. The movie was banned, picketed, derided, death threats were made, and by crowds of credulous cretins who believed that the Pythons had simply plucked these brilliant blasphemies out of the blue; but if one is to watch this film with an ounce of knowledge about the controversial issues it parodied, one will see that painstaking historical research went into the making of this masterpiece.
In the film, the Pythons cast the “virgin” Mary in a somewhat humiliating light – as a Jewish woman who had casually conceived Brian (Jesus, but not Jesus) out of wedlock with a Roman soldier, thus explaining Brian’s Roman-looking nose. Absent any knowledge of the issue being parodied, this is still a very clever and funny concept, but with a little historical knowledge, this scene is transformed into an enlightening parody on a controversy that spans nearly the entire breadth of Christian history.
According to Jewish traditions contained within numerous rabbinical works, namely, the ‘Tosefta,’ (third – fourth centuries CE)  the ‘Jerusalem/Palestinian Talmud,’ (fourth – fifth centuries CE)  the ‘Babylonian Talmud,’ (third – seventh centuries CE)  and later reiterated in the Jewish polemic, the ‘Toledoth Yeshu’ (Biography of Jesus) (tenth century),  Jesus (Sometimes, ‘son of Pandera’), was a shameful character, and in numerous traditions his mother was said to have conceived him in adultery, and in some versions of the tale, with a Roman soldier.  But the earliest of these sources dates to the third century and the earliest of these sources that mention Jesus’ “illegitimate” birth, dates to between the third and seventh centuries CE.  Also, as many scholars have noted, these unflattering descriptions of Jesus and his mother appear to be polemical in nature, drawing their adulterated narratives from pre-existing Christian sources. 
If we factor history into the equation and take into account the horrendous anti-Semitic atrocities committed by Christians, it makes sense that the rabbis sitting safely in Babylonia, might wish to sully the name of Christianity’s most adored character, but the truth is, these stories go back well before the composition of the Babylonian Talmud. In fact, some of the Talmudic and rabbinic traditions about Jesus can be found in the gospels themselves. 
One of the earliest sources we have for the claim that Mary conceived Jesus out of wedlock, comes to us from the second century philosopher Celsus, whose works have all been destroyed, but for the fragments which remain in the third century Church father Origen’s ‘Contra Celsum’ (Against Celsus).
The relevant excerpt reads as follows:
…[Celsus] accuses [Jesus] of having “invented his birth from a virgin,” and upbraids Him with being “born in a certain Jewish village, of a poor woman of the country, who gained her subsistence by spinning, and who was turned out of doors by her husband, a carpenter by trade, because she was convicted of adultery; that after being driven away by her husband, and wandering about for a time, she disgracefully gave birth to Jesus, an illegitimate child…
According to the Jewish tradition relayed by Celsus, Jesus wasn’t the bastard-son of a lying adulteress, but the lying bastard-son of an otherwise honest adulteress. Further, Celsus likely received this information about Jesus from his Jewish associates, which demonstrates that this Jewish tradition existed in the second century, if not earlier.
This still places the ‘Bastard Hypothesis’ after the composition of the original birth narratives contained within the falsely named gospels (Matthew and Luke), and is still suspect, well, only slightly less suspect than the original birth narratives, which seek to assert that the tribal deity of the Jews impregnated a Jewish virgin with a ghost version of himself. And here we arrive at the central point of this little piece. If any of the aspects of the gospel narratives are to be believed, and I would certainly stress caution in this regard, then we have to weigh the competing stories of Jesus’ conception and birth upon the basis of reasonableness and likelihood. To help us do this, I’ll call upon an abridged version of the brilliant logical formula created by William Ockham, popularly known as ‘Occam’s Razor.’
If you have two competing explanations for something, the simplest explanation is likely to be the correct one.
So, if we are to pit these two unhistorical claims against one another, which is more likely? Was Jesus the child of a virgin and a virgin-raping ghost-daddy, or did he or his mother lie about his Egypto-Grecian-styled incarnation?
If you accept the most reasonable of the two claims to be true, then you may be justified in asserting that Christianity, with its suicidal martyrs, its Dark Ages, Inquisitions, Crusades, murderous missionaries and its 40,000 confused denominations, is but the lie of either an adulteress or her illegitimate son – a lie that got way out of hand.
- Bart Ehrman. Jesus Interrupted. Harper-Collins. (2009). p. 149.
- Steven T. Katz. The Cambridge History of Judaism, Vol. 4. Cambridge University Press. (2008). p. 321.
- p. 667.
- p. 840.
- Fred Skolnik & Michael Berenbaum. Encyclopaedia Judaica. 2nd Vol. 20. Keter Publishing House. (2007). p. 29.
- Catherine M. Murphy, PhD. The Historical Jesus For Dummies. Wiley Publishing Inc. (2008). p. 270.
- Steven T. Katz. The Cambridge History of Judaism, Vol. 4. Cambridge University Press. (2008). p. 840.
- Maurice Goguel. Jesus the Nazarene: Myth or History? D Appleton and Company. (1926). p. 21; Robert Price. The Incredible Shrinking Son of Man. Prometheus Books. (2003). p. 40; G.R.S. Mead. Did Jesus Live 100 BC.? University Books (1968). Pp 135-51, 302-23, 388-413; Hugh J. Schonfield. According to the Hebrews. (1937). pp. 101, 122, 146-47.
- Jewish tradition of the faked resurrection (Stolen Body Hypothesis) found in rabbinical traditions also appears in the Gospel of “Matthew” (28:11-15).
- Philip Schaff. Ante-Nicene Fathers Vol. 4: Fathers of the Third Century: Tertullian, Part Fourth; Minucius Felix; Commodian; Origen, Parts First and Second. Grand Rapids, MI: Christian Classics Ethereal Library. 699.