Eea Family Permit Visa Dependant Step Parent

My wife is an EU citizen (German) with PR. She wants to bring over her dependent mother and step father (both non-eea citizens), but was not sure if parent implies step parent as well.

For proof of that relationship she was planning on sending her birth certificate which names her mom, and then connected to that her mom and step dad’s marriage certificate to prove he is a relative by marriage.

I guess the main question here is does parent specifically mean biological parent or can it also mean step parent?

Hopefully, this question has a straightforward answer?

From personal experience:

I know a French citizen who managed to bring her non-EEA mother and her non-EEA step-father to Belgium. And since the law is meant to be the same across the EU, the answer to your question for the UK is most likely: yes.

So keep investigating. Or maybe someone will point you to a specific paragraph that states it explicitly.

I have had confirmation from the home office, that this, in fact, applies to both biological and step-parents.