From the LGSWE;
In news and academic prose, 'who' is the overwhelming choice for selected human head nouns, eg. people, children, boys, students, etc.
However, "[I]n conversation, a different pattern is observed: that is much more common with human head nouns, almost as common as who.
[LGSWE - Table 8.6 & 8.7 - page 613]
- For Teachers