Have her apply to MIT or Caltech rather than Harvard or Stanford.
From commenter Triumph104:
For the Fall of 2015, Caltech admitted 6% of 4781 male applicants and 16% of 1725 female applicants. Stanford admitted 5% of 22,831 male applicants and 5% of 19,666 female applicants.
MIT admitted 6% of 12,750 male applicants and 13% of 5556 female applicants.
Harvard admitted 6% of 19,506 male applicants and 6% of 17,801 female applicants.
On the other hand, about 15 years ago, I was walking across the Caltech campus in Pasadena and I overheard a sophomore coed giving a tour for potential applicants and their parents. One parent asked something like “Is the workload stressful?”
The young lady hosting the tour started to respond, but then she broke down into tears.
So I imagine the answer is “Yes.”