Equity and Inclusion
The Department of Physics & Astronomy endorses McMaster's statement on Building an Inclusive Community with a Shared Purpose:
At McMaster University, an inclusive community is one in which there is real, visible and meaningful representation of the diversity evident in the wider community at all levels and in all constituencies on campus (faculty, staff, students, administration). It is a community in which all members feel safe and empowered, valued and respected for their contributions to the shared purposes of the University; research and education excellence. It is a community where the rights of all individuals and groups are protected. Inclusion occurs when an organization provides equitable access to its services, benefits and opportunities, when systems and structures facilitate full participation by all members and where members are treated equitably and fairly and are recognized for their contributions. The key ingredients are equitable access, participation (especially in decision-making processes) and equal attention to the needs and aspirations of all.
In seeking to build an inclusive community with a shared purpose, McMaster University strives to embody these values:
RESPECT; COLLABORATION; DIVERSITY
A Respectful Community is one where freedom of expression, belief, and diversity of knowledge occur in a framework of dignity, respect, and public engagement.
A Collaborative Community is one where participants jointly move the academic vision forward in respectful and non-confrontational ways, having regard for personal and collective safety and well-being.
A Diverse Community is one that enables us to learn from our differences and that affirms our shared accountability for achieving access, equity, and meaningful inclusion of under-represented groups at all levels of the campus community.
Who to talk to
In general, if a student feels that there are issues pertaining to diversity, harassment, or discrimination, they should discuss their concerns with someone that they trust and are comfortable with. Within the department, students can go to their supervisor or their TA supervisor; the Associate Chair; or the Department Chair. They can also talk to any other faculty member.
Outside the department, students can contact the Associate Dean of Graduate Studies for the Faculty of Science (email@example.com). The McMaster Ombuds office gives impartial advice to all members of the McMaster community . Students can also contact the Office of Equity & Inclusion . If the matter is related to TAing, the union may have some advice .
There are a number of groups within and outside the department who have diversity issues as part of their mandate, including the Graduate Women in Physics & Astronomy (GWIPA) and Women in Science & Engineering (WISE); McMaster Open Circles ; Queer Students Community Centre  (mostly for undergraduates) or firstname.lastname@example.org (mostly for people who are not undergraduates -- no webpage for this group yet). MSU Diversity Services  is also set up for undergraduates, but they will be able to direct you to an appropriate office/community/contact person.
Strategies to Deal with Harassment
Harassment is defined as a course of vexatious comments or conduct that is known or ought reasonably to be known to be unwelcome. For a fuller definition and more information on dealing with harassment, this page  is quite useful. To summarize
If you are being harassed, you can do some or all of the following: ask for help; tell the harasser to stop; keep a record; protect yourself; and get support. If you witness harassment, you can do some or all of the following: offer support to the target of harassment; tell the harasser to stop; make a record; and get support.
As TAs and senior members of the McMaster student community, you are advised to be a role model; set clear expectations; monitor your workplace; and contact the Equity & Inclusion Office for support and guidance.
Relevant McMaster Policies
All Human Rights and Equity Policies: 
Of particular note is the new policy on Discrimination, Harassment & Sexual Harassment: Prevention and Response. All graduate students should read this policy carefully, as you have duties and obligations as "Persons in Authority" in your roles as TAs. As a general rule, if you are approached by a student with a questionable situation, you should contact the Equity & Inclusion office for advice; but you may be called on to do more than that, so you should be aware of your responsibilities.