Oh, yes, indeed the differing participation in Computer Science of women may be of a mostly biological origin. The point is, that we don't know if it actually is. We know that there are very good (and obvious) reasons why a job involving heavy lifting might be dominated by men.
Claiming to know that physiological differences are the origin of the vastly different enrollment rates in CS schools of men and women is an ass pull.
And why aren't they interested? What you're saying is like decrying the study of gravity because you already know that things fall.
We know the what: that girls aren't interested in studying CS today in the US. In fact, their interest in pursuing a CS carer in contrast to men has sharply decreased over time since the nineties. What we don't really know is the why. And finding out the 'why' is, ahem, SCIENCE!
And you actually know why are the different sexes attracted to different professions? PROTIP: elementary school biology doesn't cut it.
We don't know to what extent this is a product of culture or a product of biology.
Always leave room to add an explanation if it doesn't work out.