WanderingTeen,
Unfortunately, the mekoros regarding intergender interactions are not taught in high school. This leaves teenagers with the impression that as long as they aren’t doing “anything serious” there is nothing wrong and the rabbis are just being farfrumpt and piling on chumras. This is not chumra, this is ikkar hadin basic halacha (that doesn’t mean it is easy, of course).
Rational,
I am no seeker of chumras and I rarely agree with Health on anything. But in this case he is absolutely right. The mekor is in Sanhedrin 75a.
The gemara reports an incident of a man who became lovesick regarding a certain woman. The doctors said that the man would die if he could not fulfill his love in some manner. The sages were consulted and said that it is better the man die. The doctors suggested only having her stand before him unclothed. The sages said it is better the man die. The doctors suggested having them converse on opposite sides of a fence (i.e. where they could not even see each other) but still the sages maintained it was forbidden.
Reb Moshe (I”M, Even HaEzer Chelek 4:60)understood this gemara to mean that conversation “derech tayva” is forbidden m’d’oraisa. Most poskim hold that it is d’rabbanan as is implied by the Rambam in Issurei Beiah 21:2 and in the Shulchan Aruch, Even HaEzer 21:1.