Ellie -- but you know now thanks to crisane. Remember every day is a school day!!
It's a bit of a faff in that you can only search on one year plus or minus 2 years. So when you are trying to discover all the children born to a couple, you simply have to go through several years AND on male and female separately.
In addition - you can search the death indexes on the GRO website and find ages at death, before they are shown on the Civil Registration Index on the normal sites.
