For a few moments there I thought I was going to have to have the birds and the bees talk with my little girl. There were a few hot flushes I can tell you because, well, she's only three.
You see, Mia is enamoured with her mum's pregnant belly and she's started asking those sorts of questions.
Thankfully, she's not talking nitty gritty just yet.
More like "How did my baby sister get in there?" and "How will she get out?"
Luckily, I've managed to avoid answering by delaying just long enough so she moves on to the next question. For some reason it's always harder for dads to talk about this kind of stuff.
My wife is far wiser and simply says "it's magic" because there are some things three-year-olds just don't need to know about. And besides, it will be a little like a magic trick for Mia when her baby sister arrives.
What there will not be is a magic wand to help her adapt to having a sibling.
For three-and-a-bit years Mia has had our undivided attention - and sharing that will take some getting used to.
At the moment it's all wide-eyed delight that she's going to have a baby sister to cuddle, play with and boss around. The reality, I fear, will be a little less rosy than Mia thinks.
And it's clear the cute wee sausage has already started thinking about what sharing mum and dad will mean. Ever since we told her she may have to stay with her auntie for a little while when mummy goes to hospital she's been asking searching questions like: "Will you stay with me forever and ever?"
It's a lot for a little one to get their head around.
Ultimately though, having a baby sister will be good to reinforce to Mia the fact that, although we love her very much, she is not the centre of the universe.
It may even knock a little of that pre-school attitude out of her that she's picked up recently. Anyway, that's another story.
In saying all that Mia is itching to meet her sister and show her how to walk, talk, and play the shopping game that she so loves.
I'm just looking forward to seeing them grow up, become mates, and no doubt have a few fights along the way too.