Student or Learner
In this sentence "Today it is illegal for anyone to help or assist someone else in taking their own life with penalties up to 14 years in prison." I used the word "someone" with "their" and lost marks for it. I thought that their was the correct possessive to use but lost marks for it a number of times in this paper. Other than saying "his/hers" (which I find cumbersome to read) how could I have written this sentence better?