So far it's all progressed exactly as I remember from GCSE biology: I've done some kissing and the upshot is I've successfully fused DNA helixes with a diagram of a female pair of hips. Right, so what next?
Well, what they didn't mention at school was that your first experience of pregnancy, after the formal introductions are out of the way - cursory waft at a due date by a GP, courtesy call from jolly midwife - is a long, lonely No Mum's Land. For six uneasy weeks, the pair of you are left alone with no evidence of offspring in the offing other than a mysterious red book, that queasy feeling of being out of your depth (dad) and that queasy feeling of violently regurgitating your breakfast (mum).
It's this sense of wandering unaided in a medical wilderness rather than the irrepressible 'Yay!' of parenthood that's been making it very tough to keep schtum about our news. I think we'd just like our hand held a bit by people who have been there. But received wisdom suggests we should not go public until our 12-week scan has confirmed there is definitely a foetus in there, and not, as my wife insists may yet be the case, 'a big pie'. The reason for the 12-week embargo is, of course, the very real threat of miscarriage, and it's an entirely sensible precaution given that the majority of these happen in the first trimester.
Despite the protocol, though, my wife and I are rubbish at keeping secrets. We spill the beans to her parents over dinner. They loll around a bit, unbalanced with delight, then tell us all about what it was like being pregnant in the '70s - all shellfish, Champagne and smoking cigarettes through your bellybutton, apparently.
In the couple of weeks since then, we've told a further smattering of family and friends, sometimes because it would have just been weird not to, and sometimes through dozy accident (tip: when inviting people round for cups of tea, hide the folic acid). Meanwhile my wife's social life has turned into a chessboard of intrigue - a game of 'hide the sobriety' played with subtly undrunk glasses of wine, lemonades disguised as gins and visits to the loo disguised as visits to the bar.
It's the bare-faced dishonesty I find exhausting. When panic led me to tell an out-and-out lie to one of our more astute friends (Suz, I'm sorry - please still let us come to your wedding), I decided I was over all the cloak-and-preggers stuff and now I can't wait for the moment of great unburdening.
In fact, I have already begun drafting our Official Pregnancy All-Friends Group Email. The OPAFGE is the accepted method of proclamation these days, and among the dads in my circle of friends, competition has been hotting up over the years to see who can make their announcement the funniest and most brutal of all. As I cast about for a way to top this for an opening line: 'After declaring our last child a partial success, my wife and I have decided to begin work on another one...' (nice one, Colin), I realise it's prudent not to take this stuff too far - it's never too early for someone to report you to social services, you know.