This statement from the "Equal Pay Bill" letter is most clearly based on a stereotype. The stereotype is that women are worth less than men, which is a deeply ingrained and harmful stereotype that has been used to justify gender inequality and discrimination. The statement implies that this stereotype is perpetuated by the lack of equal pay for women, which is a serious issue that needs to be addressed. However, the use of the stereotype in the statement detracts from the argument and may be seen as offensive or dismissive of women's abilities and contributions.