Transfemale athletes competing against cisgender females...no competition if the Trans athlete has begun Puberty...and more study is needed for transitioning before that.
Beyond that, we're talking about fellow human beings who through no fault of their own are trying to deal with Gender Dysphoria and live as happy and productive lives as possible. They need understanding and acceptance for who they are...and definitely not harassment and/or persecution, such as posters here demonstrate.
I'm more than a bit surprised at your lack of acceptance for someone who's 'different' than most others.