I also suspect the number of women who want only women attending them in a medicalised birth is very, very small.
In the UK at least, the vast majority of women (think it's about 75%) give birth attended by midwives, not doctors. And a quick Google tells me that 99% of midwives in the UK are women. So for the majority of UK women, it's probably safe to say they experience a female-centric and female-led birth.
Once into consultant-led care, or medicalised births, it's a different story in the UK, depending on what specialisms attend the birth. I suspect in most cases, if your consultant-led care is planned, and not an emergency situation, if want a female consultant, you can request and have one. It's only when there is an emergency that the choice is less practical.
If my DDs birth had been delayed by even a few minutes, she would likely have died, and possibly so would I. Speed of availability rather than sex became the defining choice.