My son wants to know what love's got to do with it?
Never mind "where do babies come from?" or the awkward follow-on question about how the sperm gets into the egg, how do you explain love?
My six-year-old son, for no good reason I could think of, asked me to explain "falling in love".
He hasn't shown any interest in girls. The ones he notices are his two aggressive sisters, who distract his play, break his building blocks or scream at each other across his careful drawing exercises.
But I shouldn't have been so surprised. I heard later that the friend he'd been playing with is in love.
While knocking a ball about, and making clay animals, they spoke about love and crushes. I cherish the image of the little boys talking about romance.
Six is young, but we're told not to miss the opportunity to discuss life and love. So I told him some of what I knew.
Falling in love is magical. It's when you can't stop thinking about somebody and when you want to spend all your time with that person. I didn't say you might forget to eat, become clumsy and feel foolish around your loved one, and that there is very little else you can do but be in love.
I didn't say this magic can feel like a sickness. And can sometimes be like a sickness. I didn't talk about heartbreak. Nor did I say falling in love can be a form of obsessive-compulsive behaviour.
Then he asked: "Can you fall in love with someone you don't like?"
Yes, I said, not entirely truthfully because real love involves someone you really do like. You might not realise it at the time, but sometimes you fall in love with somebody who isn't good for you. The person you love must make you feel good, make you happy and be kind. And you, my little boy, when you're grown up, will be kind to your lover, too.
I didn't tell him you might not know that while your senses are tap dancing you are fixating on someone horrible and cruel.
Or someone plain weird and obsessed, like Tom Cruise.
Of course there is doomed love. I didn't tell him about Romeo and Juliet, or Anna Karenina , or Othello's Desdemona.
Perhaps it's better to get him thinking about blander love. The sort that doesn't inspire classic love stories.