I'm doing some training at work and the video I'm watching says:
'The Equality Act 2010 protects people from discrimination due to protected characteristics including: race: gender, disability, sexual orientation: transgender, religion and age.'
Punctuation is all theirs. 
I've looked up the protected characteristics on the gov.uk website, and they use 'sex' rather than 'gender' and 'gender reassignment' rather than 'transgender'.
Is there a difference between the last two?
Funnily enough, they don't give pregnancy or maternity leave in their examples of protected characteristics.