Thanks, everyone, for your comments here. We've had a chat with our Insight team and we're going to be adjusting the survey and the registration page to say 'male/female/prefer not to say'.

We know there's no perfect solution here but we think this is the closest we can get to being sensitive to all parties.

Arf. Thanks @Datun. Place does need cheering up a bit this morning!

Good point @bunbunnny. Though I fear I might tip Insight over the edge if I ask them to change it again today. All the smileys in the world won't save me then! I will pass on your thoughts though for the future. It's a fair point.