The 19-year-old, who is the daughter of the former England footballer, is one of the crop of new Islanders currently taking part in the ITV2 reality show.
Much has been made of her young age of social media, especially after she was paired with 27-year-old Davide Sanclimenti.
While Michael agreed Gemma was “so achingly young”, he stood by his daughter’s participation on the show and insisted she was “mature” for her age.
In an interview with MailOnline, he said: “Much of the social media obsession about her has focused on her youth.
“She has had two years more than I had to get ready for life in the public eye.
“Also, she’s a mature 19. She’s a bit like me in that regard. I was playing for Liverpool when I was 17, and having to make friends with 23, 24, 25-year-olds.
“The bottom line is, she’s an adult and I have to trust her to make sensible decisions.”
Michael also admitted he and wife Louise have been struggling with some of the social media comments about Gemma’s personality.
“She’s the most amazing girl you could meet,” he said. “She’s clever and funny and kind. She’s not two-faced. She’s loyal, a decent person.
“She’s still our baby. I’m still my parents’ baby and I’m 42! It’s how it is.”
Earlier this week, Michael was left cringing when his fellow football pundits brought up the topic of Love Island as they hosted coverage of England’s latest game.
The most recent episode of Love Island saw Gemma recouple with Luca Bish after the pair found a connection.
However, a preview of Sunday’s episode revealed that the villa is set to be rocked by the arrival of one of Gemma’s ex-boyfriends.
Love Island continues on Sunday at 9pm on ITV2.