Let's say hypothetically for the sake of argument you are walking through a forest $F$ when you hear a croak from a pair of frogs $(f_1, f_2)$ of the same species $S$. You do not know which frog croaked. You know only males $S_m\subset S$ of this species croak and are otherwise indistinguishable from females $S_f\subset S, S_m\cap S_f=\emptyset$. Croaking $X$ is random and independent from other frogs, females and males exist in equal proportion $|S_f| = |S_m|$ and in arbitrarily large amounts, and frogs congregate randomly and independent of other frogs.

What is the probability that both frogs are male i.e. $P(f_1\subset S_m \wedge f_2\subset S_m) = ?$

This is NOT a homework problem, jannies ($j\subset J$), as there are no frogs $f$ in my house $H$.