The phrase "a subject for which" is correct and usable in written English.
It can be used when introducing a topic or theme that is being discussed or analyzed, often in academic or formal contexts.
Example: "The research paper focuses on a subject for which there is limited existing literature."
Alternatives: "a topic for which" or "an issue for which".
Gems are a subject for which Ms. Deneuve has what you might understate as an affinity.
That encouraged him to concentrate on chemistry, a subject for which he clearly had a gift.
Her latest novel boldly takes a religious theme, a subject for which I am also known, but I bet she does it differently and with style.
He has performed a vital service by compiling sensible advice on a subject for which sensible advice is in short supply.
And the last thing to wish for is to be subjected to artists' politics, a subject for which they're usually as ill-equipped as are politicians to make judgments about art.
I taught him everything I knew about scorpions and their tarantula cousins, too, and began to instruct him in the natural sciences in general and medicine in particular, a subject for which he seemed to have a special affinity.
Many schools will organize a special course on any subject for which there is a demand.
Automatic identification of orthologs is a complex subject for which many sophisticated methods have been developed, the most suitable one being application dependent [ 37].
We therefore employed a k-nearest-neighbor imputation approach [ 56], in which missing values were replaced based upon the k = 20 nearest neighbors of a given subject for which data was missing.
Huntsville also has moved to an online curriculum in all subjects, for which it pays Pearson $200 a year per student.
US regulation explicitly mentions neglected or abused children as a subject population for which a waiver of parental consent might be appropriate.
