A person in full astronaut suit and gear trains in an underwater lab as a scuba diver assists.
A female astronaut adjusting to the feeling of low gravity by training underwater.
The first sentence does not imply that the person in astronaut gear is a female.
Not all astronauts are female. Just because the astronaut is underwater does not mean they are adjusting to the feeling of low gravity.
The person is not necessarily female and just because they are training under the water does not necessarily mean they are adjusting to low gravity.