Need Help with Phrasology

[Deflare]

I'm doing a report for my biology class about mechanisms of sex change, such as certian species of frog are capable of. However, I'm having difficulty finding resource materials, as I don't know the 'official' term for this type of sex change. Merely searching for 'sex change' brings in... interesting responses.

I would like to know the official, 'sciencey' term for naturally-occurring sex change, as well as advice on how to find more information for this topic.

Thank you.

[Deflare]

Update: I've been informed of the phrase in a different thread. Thanks for all your help.