it is not a personal attack on you, but it still doesn’t makes sense.

if someone asks “can i find good french restaurant in this city?” “no” is not the correct answer, just because i, or even majority of people, don’t know one.

it IS possible to tell sex of the dog. it depends on the breed, it may be easier with some, and people who are well familiar with the specific breed will be more successful than just random person.

but the fact that lot of people will answer incorrectly, or don’t care, doesn’t imply it is not possible.