Thus, the question in my mind about if they want to play with men sexually, should 'we' (parents) stop them? Pros and cons discussion.

We cannot stop them.

Those who do not, is either because of lack of interest, lack of luck in setting up the encounters, or lack of the abilities to establish a rapport with any potential partner. Not because parents stopped them.

What we can do is cultivate their minds so their criterion is well developed for deciding whom to pursue sex with instead of another; and build a strong relationship where she will be confident to speak with you about the subject and relying that you will listen to her carefully and any advice you give will be unprejudiced and nonjudgmental and making a real effort to be unbiased.

If we do these two, then they will know to stop what needs to be stopped. If we don't, they will unable or far less able to. But "we" did not stop it. She did herself.