  The discussion around the problematic practice of gendering humanoid robots
has risen to the foreground in the last few years. To lay the basis for a
thorough understanding of how robot's "gender" has been understood within the
Human-Robot Interaction (HRI) community - i.e., how it has been manipulated, in
which contexts, and which effects it has yield on people's perceptions and
interactions with robots - we performed a scoping review of the literature. We
identified 553 papers relevant for our review retrieved from 5 different
databases. The final sample of reviewed papers included 35 papers written
between 2005 and 2021, which involved a total of 3902 participants. In this
article, we thoroughly summarize these papers by reporting information about
their objectives and assumptions on gender (i.e., definitions and reasons to
manipulate gender), their manipulation of robot's "gender" (i.e., gender cues
and manipulation checks), their experimental designs (e.g., demographics of
participants, employed robots), and their results (i.e., main and interaction
effects). The review reveals that robot's "gender" does not affect crucial
constructs for the HRI, such as likability and acceptance, but rather bears its
strongest effect on stereotyping. We leverage our different epistemological
backgrounds in Social Robotics and Gender Studies to provide a comprehensive
interdisciplinary perspective on the results of the review and suggest ways to
move forward in the field of HRI.
