Discuss and learn French: French vocabulary, French grammar, French culture etc.
I've seen it written both ways. What are the grammatical rules that govern the choice between either option? What is the difference in translation?
If there are no "rules" about it, and the following translations are correct, that is good enough for me:
Non, je n’ai pas de sœur. | No, I don't have a sister.
Non, je n’ai pas de sœurs. | No, I don't have any sisters.
No ,I wouldn't worry about it. Both seem correct and I think your translations are good.
There are alternatives of course and if you were translating a poem or you were concerned about style and context you might express it differently ......