I couldn't find anything in the T&C's regarding gender specific (or male exclusion).
But remember that, the survey is about “Women’s Health and Well-being”.
The prize is also female orientated.
I guess you could ask your female partner what their “weight is like?” … “are they eating healthy?” … “how they are feeling mentally?” … "period/menstrual discussion with your doc?" … etc
As those are some of the Q’s in the survey.
The survey(/results) is primary reason as to why this exists.
The prize is just there to entice more to enter.
But hey,
Doesn’t seem like there is any actual barrier to prevent a male from entering/winning.
well that's just taken equality back 10 years ;)