We know that family can have a lot of impact on academic direction of a student, but is it appropriate for a student to have a supervisor/advisor who is also a family member? For example, a dad might supervise their son. What would make this more or less appropriate? What conditions might be required to make this appropriate?
Counterexamples notwithstanding, the practice certainly raises all sorts of questions about conflicts of interest: is the adviser providing unbiased advice, is the adviser unbiased in their assessment of the academic proficiency of the candidate, is the advisee independent to choose their research direction, etc.
In cases like this, nobody looks good -- people wonder about the judgment of the adviser, they wonder about the actual quality of the candidate if papers are jointly written, and they wonder about what's going on in the department to let such things happen. As a consequence, people and departments are generally well advised not to let this happen, simply because the perception of a conflict of interest is oftentimes just as bad as the actuality of something improper happening.
I'm sure that such cases might happen (and frequently do for earlier education, like elementary school), but they should not happen at the graduate student level.
All of the usual concerns of nepotism and coercion apply, just as for any other professional relationship. Moreover, at the graduate level, there are so many different options available and an emphasis placed on intellectual "cross-fertilization" that means most institutions strongly prefer to send their students elsewhere for future positions. I cannot then see how a graduate student supervised by their own parent would be anything but a rather dubious relationship at multiple levels.
Yes, I happen to know a researcher in country A supervising his own wife's PhD :)
They are both from country B, and come from the same city. He was her lecturer during her undergraduate in that city. He then moved to country A, and they had been dating before she started her PhD in his institution.
After they had got married, she changed to another supervisor. During her PhD, she published 8 papers: her husband was the first author in 7 of them, and the second author in the 8th (in which she was the first author). The new supervisor only co-authored 3 papers. So I guess, he continued to mentor her even after she had changed supervisor.
She graduated last year, and seems to have a good job in industry, according to her Linkedin profile. He is now director of research in his institution, having published more than 100 papers. Their baby is also nearly one year old now.
A is one of the most developed countries in Europe. B is also in Europe, but not in the level of A.
Fact just for fun:
Actually, this question reminds me the story of the Curie family.
Irène Joliot-Curie, a Nobel laureate, supervised both of her children, who are also notable scientists.
Irène herself was supervised by Paul Langevin, grandfather-in-law of her daughter, former lover of her mother, and former Phd student of her father. What a complicated relationship.
I can see why some might raise an eyebrow at this arrangement – from both perspectives. Other students might wonder if the thesis student is getting preferential treatment. Other faculty might wonder if the advisor is applying the same standards of rigor.
I think this might be avoided if the parent (or other relative) offered to serve on the committee, but not take on the role of primary advisor. If my daughter was in graduate school and asked me to be her advisor, that's probably what I would recommend: "I'll be on your committee, but you'll have to find someone else to be your main advisor."
That said, people are citing counterexamples; evidently, the practice is not universally verboten. So long as the research is quality reseach that withstands any scrutiny, I suppose it can be made to work. However, if the student is coasting along with research of marginal quality, this has potential to backfire.
Back to the hypothetical between me and my daughter: if I were to agree to such an arrangement, I'd want to be very sure she could do some outstanding research independently, to ward off any conflict-of-interest allegations.
If someone's dad is the best in the field they like, and they were accepted by the department to the graduate program, what's the problem?
Could it lead to abuse? Sure. But why shouldn't this person be with the best? Matter of fact, this person probably knows more about the field than any other student, having being brought up in a certain environment.
Just to amuse readers: There's a book in optics written by: "Pedrotti, Pedrotti, and Pedrotti".