@Reluctantadult
Thanks Zombie! I'm the last on your list.
Hooray!
It's quite a large subject encompassing many issues.
I've not read it, but lots of people recommend Helen Joyce's book 'trans'. There's also Kathleen Stock's 'Material Girls'.
Some other suggestions here:
sex-matters.org/bookshelf/
The problem in a nutshell is that women, as a 'minority' in the sense that they face structural inequalities, have certain protections in law. These are enshrined in the Equality Act. (Nine protected characteristics; sex is one).
The 'Gender Recognition Act' was introduced subsequently and suggests that males can effectively become female. This is where the 'transwomen are women' slogan comes into play.
Feminists believe that allowing males to identify into femalehood risks sweeping away women's rights that are protected in law.
If anyone can 'identify' as a woman, and there is no clear definition of woman, then how can we protect our rights?
This can be illustrated by situations like the males identifying as women to get the places reserved for women in affirmative action:
www.theguardian.com/world/2018/jun/22/mexico-elections-fake-transgender-candidates-disqualified
There are also some risks presented by males being increasingly able to access female spaces.
For example, a male identified as a female and was placed on a female ward in hospital. He raped another patient, who was then told by the NHS that the rape couldn't have happened because 'there were no men present'.
Males are being place in women's prisons. There have been sexual assaults by males in women's prisons.
Most feminists really don't care how anyone 'identifies', so long as they don't impinge on women's rights to privacy, dignity, and equity.