Four in five UK parents have been stumped by a science question posed by their children, a poll has suggested.
The top three most-asked questions were: "Where do babies come from?", "What makes a rainbow?" and "Why is the sky blue?".
More than half of the 1,002 parents surveyed thought their children knew more about science than they did.
And 20% of parents said they felt silly when they did not know the answer to their children's questions.
The survey of UK parents with children aged five to 16 was carried out to mark the launch of a new website by the Department for Business, Innovation and Skills.
The website - Science: So what? So everything - gives information to parents on answering those tricky questions from children, as well as downloadable activity sheets and ideas of places to visit.
How to answer about where babies come from? The website explains that babies are created when a cell from the mother and a cell from the father join together or "fuse".
After the two cells fuse, the site goes on, they divide over and over again to create a ball of cells called an embryo that goes on to become a baby that grows inside the mother for nine months.
The website explains how a rainbow is made from light and water - with help from the sun.
And the sky is blue, it says, because the sun produces white light which is made up of all the colours of the rainbow.
But a clear, cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more easily than they do red light.
'Incredibly curious'
Former Tomorrow's World presenter Lindsey Fallow said: "Kids are incredibly curious, constantly wondering about the world around them. Why is the sky blue? How do flowers grow? There's no end to the things they want to know.
"An inquisitive mind is a good thing, but can leave parents in a sticky situation if they don't know the answers."
Minister for Science and Innovation - and father of five - Lord Drayson said: "Like all parents, I've had to cope with many questions from my children.
"The Science: So what? So everything website will help parents get ready for the onslaught of questions their kids throw at them and fuel their children's curiosity at the same time."
