Both, and more.
First off, let's reiterate what has been said repeatedly: females are not seeking to exclude transgender people because they are trans; females are refusing to surrender the already existing right to exclude males. Transwomen are male.
Second, there is an actual real risk to females from males. Not every male is a risk, just like not every person walking around in public armed with an Ar-15 is a risk. But statistically speaking, males are a risk to females, just like people with high-powered rifles are a risk to everyone around them. It is an actual risk in aggregate, even if it is not a specific risk in the individual. Furthermore, just as with a person armed with an assault rifle,
observers have no way of knowing whether that armed person is or is not a risk. Males are enough of a risk to females that it is rational and reasonable to assume that any male has the capacity to be a risk. 1 in 3 females has been subjected to sexual assault in their lives. 1 in 6 females has been subjected to an attempted or completed rape in their lifetime. 90% of the victims of sexual assault are female. 15% of sexual assaults occur in open public places. 10% occur in closed public places. (
RAINN Reference). These are not negligible statistics. These aren't occurrences that are so rare they can be ignored.
These are real risks. And 98% of those assaults are perpetrated
by males. Note that those statistics do not include sexual harassment, voyeurism, or flashing. Those also happen, and females are the overwhelming majority of victims.
Third, transwomen commit violent crimes at about the same rate as cismen do. They both commit crimes at about the same rate as all males. Transmen commit violent crimes at a lower rate than cismen, but at a higher rate than ciswomen. That means that the risk of assault from a transwomen is no different than the risk of assault from a cisman. (
FPFW Reference)
Lastly, most females don't have an objection to a surgically transitioned transsexual woman in our spaces. We have an objection to self-declared transwomen in our spaces. Because we have an objection to
penises in our spaces.