Smelly It's not petition, it is a consultation for you to put forward your views.
It is your chance to put forward your views on whether you think single sex spaces / exemptions are important or not.
So if you wouldn't mind your 14yo DD sharing a room with a male bodied person without your knowledge on school trip, you can say so.
Similarly if you don't mind male bodies in girls swimming changing rooms, or in female toilets, or female prisons.
Noting that under new definitions trans people will be able to access these spaces based on their say so, without any need to have had operations, hormone treatment or even be under the care of doctors.
Also that male bodied people may be able to identify into female sport and compete against females even where their male bodies give them an inherent advantage (which is why sport is sex segregated).
But as I said, if you don't mind your teen DD going on a school trip sharing with a male bodied person, potentially coming back pregnant, you can say so in the consultation. Similarly if you don't feel girls/women should have the space to e.g. deal with periods in their own sex based toilets, you can say in the consultation it is OK.