Not a parent yet, but I was the oldest among six cousins. At school I was the go-to person to give people the birds and the bees talk right from age 10 (because I read a lot). But when my sister began menstruating, I couldn't bring myself to even face her or give her the talk. I hid for a week.

It just feels like they have stopped being your little one and grown up and you don't know how to relate to them anymore. And also, the nature of your relationship has involved no discussion of any humping so far, so you don't want to mess it up by starting.

The important thing though is to be grown up enough to recognise this and weigh the awkwardness against potential misinformation and bad decisions and forge ahead.

When I found my sister had a boyfriend, I sat her down for a really awkward talk. She got really offended and thought I was accusing her and her boyfriend of being irresponsible. A week later she thanked me. We still don't talk about sex, but she knows I'm around if she wants.