[est31]

The particular headline pattern is used a lot and 99% of the time it indeed is at the front of opinion pieces written by individuals. But this time, it's different. In the syntax, in this specific form, the plural and the singular come out the same. E.g. in the sentence "I accompanied my friend to his parent's house", it can be either the house of his single mom/dad or the house of his two parents living together.

[agalunar]

Like @bdsa points out with their example, the singular and plural are actually spelled differently, viz. "parent's house" and "parents' house", despite being pronounced the same way.

https://en.wikipedia.org/wiki/English_possessive#Nouns_and_n...

[est31]

Oh that's interesting, thanks! Not a native speaker but I dimly remember hearing about this in english class, thanks for reminding.

I guess then the PhD student is indeed grammatically a singular then. It can still refer to a PhD student in general though instead of a particular one.

https://www.rit.edu/ntid/sea/processes/articles/grammatical/...

[wahahah]

I pronouce the latter as ~parent-siz; having them the same never sat right with me.

[bdsa]

"I accompanied my friend to his parents' house"