Can I say?
1 If I and the hearer don't know the sex, can I say both:
a. If you meet someone today, that person / this person had better be a doctor.
b. If you meet someone today, they had better be a doctor.
2 If I and the hearer don't know the sex, can I say both:
a. There was someone who snuck into my house last night.
- That person was a thief, weren't they?
b. There was someone who snuck into my house last night.
- They were a thief, weren't they?
Thanks!