This is my first semester being a TA. When students email me and include personal reasons (e.g. sick family member or mental health struggles) when they ask for things like extensions or to switch recitation slots, how much detail should I include when raising these issues to the professor teaching the class? I want to be careful about respecting their privacy, but also making sure that I'm not overstepping as a TA. I'm way overthinking this, but like I said, it's my first time TA-ing!
Since the professor is ultimately responsible for the class and for the student outcomes, there is very little that should not be shared. Many things need to be shared to protect student welfare, in fact, and you are probably not in a position to make decisions.
Something like mental health issues in particular, including feelings of suicide, need to be shared since you aren't a mental health professional and the professor has more experience (though isn't a professional either). The professor probably knows the appropriate response, such as referral to a counseling office.
Trivial things need not be shared, but anything that potentially affects student outcomes and might require interventions should be.
You can also ask the professor for general guidance on this. In fact, if you have group meetings it would be useful to do it there so that all the TAs get the same advice.
When it is sent to your address you may not even be allowed to share it. Here it is important to distinguish, if the student had the expectation to reach you as a person (possibly trusting you more than the professor) or the expectation to reach some lecture related address which may spread the e-mail to different people, rely it to a mailing list or post it into some internal chat system.
I think it is reasonable to assume that an e-mail sent to "firstname.lastname@" is meant not to be shared with other persons without asking, while one can assume that mails to an address that does not specify the recipients before, like "lecture@" can be shared with other people which would be plausible recipients of the mails to such an address.
But are you sure your prof needs and wants to know? He probably only needs the summary, not the details. And students don't even need to share details with you (but usually will even when not asked), but only have to tell the examination office when they ask for extended deadlines and so on. And the examination office has strict privacy requirements, which protect the students.
When in doubt, you can always ask the student if you may share the information, or ask them to re-send the e-mail to the professor, or the examination office, or whoever gets the last word on excusing students for sickness. Another reason for this is to stay on the safe side yourself. When you acknowledge something to the student you may be liable when they try to sue the university.
Let's say you answered that their sickness is a valid reason and you believe them and the examination office says they are excluded because they didn't provide proof. Then they may try to sue because you promised something and it wasn't obvious to them that you are not in the position to make such promises. Or the other way round they take your word and don't get a sickness certificate and later on they have a disadvantage because of it.
Because of such issues it's best to advise the student to contact the relevant people, who can and must make binding promises. When you direct them to the examination office and the examination office says everything's alright, then they can be sure and having them get the confirmation from there is the best for you and the student.
I'd like to add a few points mainly to @DikranMarsupial's and @all's answers.
First of all, I'd like to thank you for being careful about student privacy.
You can always put the case in anonymized/pseudonymized fashion to your prof. E.g. saying, "A student asks for extension because of private reasons. From what they told me, I think it's genuine. Is that something I can decide? On what reasons should I grant the extension, on what reasons not?"
Even better would be to ask/organize a session of all involved with the course where the prof outlines the policy. You may start an (anonymized) case collection for future use.
Personally*, I'd "negotiate" with the student, telling them that you cannot decide this on your own and will have to consult the professor. Offer that you put the case in anonymized fashion but ask them how they want you to proceed in case the prof asks for details. I.e., whether they want you reveal details in that case or rather keep their privacy at the cost of not getting the extension.
*I'm not a junior TA any more. With a standing of almost 20 a of professional experience I'd take a stand shielding a student's privacy against any head of course, professor or institute director where I judge that is what needs to be done.
You mention mental health problems revealed: a privacy-friendly way of asking your prof would e.g. be "In case a student reveals mental health problems, where do I refer them? Do I need to inform someone or do I just tell the student where they can go for help?"
Personally (and according to how things work where I am), I'd possibly tell the student anyways that they may want to consider getting a medical certificate. These medical certificates over here say basically "X is unable to work". They don't reveal reason/diagnosis but they legally mean that the student must get appropriate accommodation.
(BTW, university policy may anyways require the student to bring one)
student revealing too much private information: you may find that students tell you more than is actually required, and more than you'd have liked to know (see next point).
It may be important feedback to the student that you think they revealed more private information than necessary.
It may be stressful to you to know private details the student volunteered (e.g. in case of health or harrassment). This is part of the TAing/teaching profession, although likely noone ever taught you about it. And it is part of the teaching profession* that you must keep this information appropriately private.
I'm writing this because I've witnessed an occasion where private student information was inappropriately revealed by a head of course. And I think this happened (also) because the head of course needed to relieve their stress by telling someone (which turned out to be a whole group of TAs). This was all very sympathetic, but still definitively inappropriate and unprofessional. All we needed to know was that in case of X happening, we should do Y.
Some professions (medical, psychological, pastors, ...) regularly face similar stress. They have supervision processes established to deal with this in a way that doesn't violate privacy.
In case you need that, it's fine to talk to someone in a way that keeps the student anonymous (maybe not even mentioning it's one of your students). One key thing to keep in mind here is: your close colleagues or friends from the department/university are not a good choice: the risk that the student's identity is accidentally revealed by circumstances entirely outside your control is substantial.
*It's actually not that rare: If you move to industry and become team lead or manager, similar things are likely to happen. Even if you volunteer as trainer in the local sports team, head a scout group, ...
Make sure you are aware of the policy for granting extensions at your university. It is possible that the prof is not involved in the process. At my university, each department has an "extenuating circumstances panel", which has the discretion to grant extensions etc. rather than being dealt with informally by the teaching team. The main reason for this is to limit the number of faculty that need to know personal information that the student may not want widely known, but also to ensure consistency and fairness across courses/modules.
The "golden rule" is quite useful in such situations, consider whether you would want the prof to know the information if you were the student and act accordingly. You can always ask the student if they mind you passing on the information.
When in doubt just cc your professor on your response email. Calling in sick or other small things not really worth it. If you're actually worrying about the student, it's usually best to call the professor. Most schools have an anonymous system to refer students to people that can actually do something about mental health.
US Specific (non GDRP): If it's concerning a student in a course, the student should have very little expectation of privacy over any communication you have about it with the course director.
Much of what the prof would like communication about is going to be up to the prof. For individual types of scenarios, like a student asking for an extension, for some courses TAs may be empowered to make those decisions, and for others, they may not be. Even if you are empowered to make such decisions on your own, many profs would still want to know who is handing in work late, and when it comes in.
Bottom line, the prof has responsibility for teaching the students and issuing a fair grade based upon performance, and is entitled to all the information surrounding that endeavor. Sometimes a prof may allow TAs to make some decisions, but that doesn't relieve profs of their responsibility, and they might choose to keep track of things.