I've just had one of those "duh!" moments. You know, when something completely obvious finally penetrates through your thick skull.
How many times have I read through (or skipped over - it's not exactly riveting) the alleged genealogies of Jesus in Matthew and Luke. These passages have proven to be a minefield of bad exegesis over the centuries. The two disagree, and given that there's supposed to be no genetic contribution to Jesus from Joseph's side anyway, the whole purpose seems a bit irrelevant.
Of course there are the Josh McDowell types, eager to race in and explain it all away, but then they would, wouldn't they? Working back from the conclusion to fiddle with the evidence till it fits... not a good look.
Then a light snapped on, courtesy of Julie Galambusch. In her book The Reluctant Parting she writes:
Matthew begins his gospel with a rather quaint nod to tradition: a genealogy of Jesus modeled on the "begats" of the Hebrew Bible. Matt. 1:2-16 is based loosely on 1 Chron. 3:1-3, but with the generations juggled in order to divide Jewish history into three distinct, fourteen-generation epochs... Matthew seeks to demonstrate numerologically (a practice called gematria in Hebrew) that the moment for the messiah's birth has arrived.
That's it - gematria! Forget all the tortuous apologetic drivel from McDowell, and even much of the painstaking eisegesis in the commentaries, we're talking numerology. Matthew wasn't completely incompetent after all, nor was he trying to be dishonest by the standards of his time. As a Jewish scribe he is doing something quite predictable, and something McDowell himself would understand in the event that he had a moment of honest clarity: he's fiddling with the numbers to make them say what he needs them to say - but (as I'm sure they'd both assure us) all in a good cause.