Stepbrothers and stepsisters vs stepsiblings

[Tom]

Hi

Could you please tell me if both of the following sentences sound natural to you? The meaning is the same.

[Conchita]

Both sentences sound natural, in my opinion (or perhaps I should say 'in my ears').

Personally, I'd say 'stepbrothers and sisters'. Also, the word 'sibling' sounds a bit formal to me.