I have both. My individual therapist is a dude and the therapist that leads my trauma survivor group is a lady.
I think it helps me to have the opposite gender as my individual therapist because it's good practice for me to learn to trust and open up to a man and share deeply personal things. I haven't had very good success at being able to navigate a one on one relationship with a woman therapist because I tend to take on a masculine energy when put in that situation.
On the other hand, the group therapist knows what it's like to be a girl - and that's really helpful too.
I think what's more effective depends on the person and what they're working on in therapy.
I've had two therapists in my life. One of them was a man and one of them was a woman. I don't think it had anything to do with their respective genders but I got more out of the female therapist.
It was a bit strange though because my therapist was like "work hot". You know like the kind of woman that you normally wouldn't take a second look at but eventually you start to think they are hot. So, I don't think I held back but I think I typically act different around women than men, so IDK.