Yes, if I hear "tāがtāを呼んだ" in Chinese, I cannot distinguish between "他，她，它". It must depends on the context. If I get only one sentence,I would try to convince myself that it wouldn't need to understand.
他 is usually used for saying ‘he’. But it can be gender neutral as well. When you want to address a group of people consisting of only male or involving both male and female, you can say 他們, meaning them (彼たち) You can also use this word when you don’t know the gender of the person / group.
note: we seldom use 他們 for addressing a group of girls
她 is specifically used for female as it’s radical is 女. Therefore, we usually say 她 when we want to say ‘she’, instead of using 他. You can also say 她們 when there is a group of girls. (彼女たち)
它 is used for addressing non-human and non-living things.
Therefore, when you say 「彼が彼女を呼んだ」, you’re trying to say ‘he called her’ (please correct me if I’m wrong) Then that would be 他叫了她