Sex = what you are... Gonads, gametes, genitals
Gender = How you feel in relation to your sex; specifically in relation to society's stereotypical beliefs about how men and women should behave (leading to behaviors that are typically 'masculine' or 'feminine' at an individual level).
Things I do because I'm female: deal with periods, give birth, lactate
Things I do that may or may not be feminine: wear lipstick. Or not. Be a hairdresser. Or not. Play football. Or not.
I can never support the conflation of sex and gender which is rife in this article.
I'd hate for anyone to feel bad about their typically 'masculine' or 'feminine' behaviours.
But I'd defend to the last that men and women are different at a population level and that women in particular have specific sex-based needs in relation to health, safeguarding, protection from abuse, criminal justice and sport etc.
Also we should not get confused between society-level approaches ('women need to have safe spaces') and responses to very individual issues ("that man feels more in tune with himself when he wears a skirt").
That writing is a load of muddled, dangerous pseudo- something or other.