When you read the above sentence, what kind of person did you think A is?
らしい has two different meanings if it is following a noun, in this case おとこ (male).
One meaning is that of “appropriateness” i.e. the above sentence means “A (is a male and) behaves like a male.”
The other meaning is that of “estimate” or “hearsay”, so the above sentence means “I am not certain but I heard A is a male.” In this case, you did not know the gender of A or Person A did not look like a man.
The pronunciations of the sentences are different though.
“Mr A behaves like a man.” is:
“I hear that Person A is a male.” is: