system
Given the following post, respond as if you're commenting on Reddit:
human
Is Academic Incest still a concern?

Good afternoon, all!

I am currently in the process of applying/(im)patiently waiting for PhD admissions and funding to be released. People in academia often discuss the negative implications with doing your Bachelors, Masters, and Doctoral degrees at the same university. I was wondering if this is still the case?

I went to a top 5 program (US, social science) at a R1 university and graduated two years ago with my Bachelors degree. I’ve been doing research at other organizations and schools since then. Now as I apply to PhD programs, my top-choice school is my undergrad institution because of aligning research interests and potential PIs.

Would completing all three degrees at the same institution have any negative implications for finding TT jobs after graduation? Am I screwing myself if I went to this university?

I appreciate any guidance you all can provide!
gpt
It's more of a general warning, not a hard-and-fast rule. 

The worst case is one that I've seen play out a few times: A student completes all of their degrees at the one (middling or lower ranked) institution, within the one group, for whatever reason. It isn't a great university for their field and doesn't host conferences, so outside academics rarely visit. Their $3000 of conference and travel funding is quickly used up for only a few conferences. They learn a small number of techniques and schools of thought. By the end of their PhD, they've only meet a few people in the field and have worked directly with far fewer, so they can't be hired by their alma mater but they have little chance of being hired elsewhere either. 

If the institution you're looking at it is a very prestigious place, is the best in your area of research, you're working with different people, and/or you'll go out of your way to make external contacts, it doesn't have to be a kiss of death or even a weakness.