According to the University of California, Berkeley website:
The field of gender and women’s studies emerged from the contemporary feminist movement with the initial goal of bringing women and their experiences more fully into knowledge. The Berkeley Women’s Studies Program was founded in 1976, bringing scholars from many different disciplines together to introduce the subject of women into serious academic inquiry. Our courses have long considered the position of women throughout history, across the world, and in different economic, ethnic and racial groups.
As we have expanded the content of the traditional curriculum, we have re-evaluated methods and models as they have succeeded or failed to include the experiences of women and the dynamics of gender. We have adapted the ideas and research methods of a wide range of academic disciplines, and we have produced our own body of feminist theory and strategies for engaging in transdisciplinary research and teaching.
Students learn to apply the methods and theories of social scientists, historians, literary critics, etc., to the study of gender.
Clearly, Gender Studies may include science, but it is also inclusive of history and literature. Therefore I think it's fair to say that Gender Studies includes science, but is not limited to science.
The summary page finishes with this sentence:
[Students] explore a growing body of feminist theory that revises our understanding of gender, society and culture.
From another part of UC Berkeley's website on the Gender and Women's Studies Department:
The Gender and Women's Studies Department promotes engaged scholarship through our unique internship courses. Students commit to working with a community-based organization for a minimum of three hours a week for the semester. The hope and challenge of these courses is to go beyond standard educational models in which learning is bound by the classroom and confined to the University. This effort to bridge the gap between the University — as a place of study — and community organizations — as agents of action, grows from the urgent need for opportunities to engage in a coordinated exploration where theory and action inform each other.
The department does not currently offer a graduate program. A Designated Emphasis (DE) in Women, Gender, and Sexuality is offered by the Graduate Group in Women, Gender, and Sexuality.