What is the primary reason a girl cannot wear a two piece bathing suit in a swim unit

[Demona]

is it because it is impractical when practicing swimming? Does a girls stomach distract the boys in the class or something? It is funny because boys are allowed to wear their swim trunks and nothing else

[Abnormal]

Because one piece swimsuits are designed specifically for swimming, two piece swimsuits were designed because they make a woman look sexy and that's not the message the school probably wants to send.