I found a sentence in this answer:
"Another example: You work in a kindergarten, and one day a child starts to walk in a strange way, and saying he broke his legs. You examine and find nothing wrong. Then you can reasonably infer that one of his parents broke their legs, since children then often actuate as described,"
I thought this should be corrected to be:
"Then you can reasonably infer that one of his parents broke his/her legs,"
And logically "legs" should be leg(s) given that if one walks in a strange way it doesn't necessarily mean that his/her two legs are hurt.