As a parent you eventually learn to shore yourself against those uncomfortable questions from your offspring, but not all uncomfortable questions are created equally, and right up there with 'Mummy, where did I come from?' is the question: 'Am I your favourite?'
I can't stress the anxiety this can cause in an unguarded moment. Especially when said offspring just won't accept a diplomatic 'You're both my favourites' for an answer.
When they invariably push me for more I tell my children that it's biologically impossible for a mother to love one child more than another (note to self to sit them in front of Sophie's Choice when they're old enough).
But it seems I may have been a little disingenuous.
Last week, US research by the University of California published in the prestigious Journal of Family Psychology found that 70 per cent of mothers admitted to favouring one child over another.
The article hit a nerve. I couldn't stop thinking about it, and mulled over its every detail. Like its participants, we, too, were a family of two parents and two children, where the children were born within four years of each other. So, on paper, anyway, the article seemed to have been written for us.
I wasn't the only one who thought this, as I discovered while visiting my parents. As we all chatted under the pergola, and the children played noisily in the garden, Dad turned to me and asked me point blank, 'Well, do you have a favourite?'
Of course, I was taken aback (although after 47 years, you'd have thought that I would have been ready for Dad's impromptu interrogation). After exchanging glances with my husband, I tried my best to explain that this was impossible due to the fact that I wanted to become a mother so badly that I was just so grateful to have been given the opportunity twice.
"One of Dad's clearest memories is of his mother saying to him: 'If your brother had lived, you would never have been born.'"
Dad, however, wouldn't be silenced. 'Come on,' he baited. 'Surely, you love (my eldest son) more because he is number one?'
When it comes to my 82-year-old father it doesn't take a psychologist to work out that there was more to his question than met the ear. Born into what was then Communist Yugoslavia, Dad was the youngest son to parents who were brought together in what was essentially an arranged