I have always been upfront with my two boys about the egg and sperm and the little baby growing in the mummy's tummy; it was just how it got there that I tended to glaze over. On the occasions they've walked in on us in compromising positions, we've managed to pass it off as 'a game', 'a dance' and once, 'a very bad dream'.

When my eldest was seven, I fell pregnant with his little brother and thought it was time for some honest talking in the house. My son deserved the truth, a point that was brought home to me when he overheard me telling a friend that the new baby was an accident. He approached me with a look of horror on his face and said,

"Mummy, what sort of an accident makes you have a baby?!"

So I bought him two books that promised to explain.

The first was 'How Was I Born'? which was Swedish, so I should have been prepared for a photograph showing Daddy's penis inside Mummy's vagina, like a pornographic x-ray, while his hands simultaneously caressed her breasts and labia. Bloody Hell. In order to protect my innocent little darling I carefully tore out the offending page and threw it away, thus leaving him with a story that didn't make a whole lot of sense:

Daddy's testicles are full of sperm and when daddy's penis is erect... RIP RIP RIP... The baby changes and grows a lot when in Mummy's womb.

I then retreated with some relief to an Usborne lift-the-flap book called 'How are Babies made?' which is delivers the facts without scaring you, albeit in a rather whimsical style. The illustration of the egg for example is orange. It says, 'Yoo Hoo, over here', in its best come hither voice while the sperm - yellow for some reason - swim frantically toward it, expressing sentiments such as - 'Come on, there's the egg'! 'I'm never going to get there!' 'Nor me' and 'Hey, I got here first!'