She is subtle about it

While Tiffany would love to just confront Jenny about this, there is simply too much of a chance for them to start yelling and then her parents would start asking questions. Worst case, it may end their friendship right after Jenny put in effort to stay friends. Instead, Tiffany let her brains come up with a plan to trick Jenny into coming out.
She takes her smartphone and searches some new article she’s read a while ago. If only she can find it before Jenny comes back.

A little later Jenny comes back, complaining about her mother.
“Sorry about that. Parents … you know, right.”
“At least they’re not as bad as politicians.” Tiffany says while staring at her smartphone.
Jenny takes a seat next Tiffany and joins her at looking what’s on the phone.
“What about them this time?” Jenny asks.
“Just reading a news article about a family-values/anti-gay politician who got caught having a gay affair.” Tiffany says, explaining the article she’s got on her phone.
“Wait …” Jenny says with a confused look. “If he has gay sex why would he be anti-gay? That doesn’t make any sense.”
“Well, I heard a theory.” Tiffany says. “Supposedly, these are people who grew up in extremely religious environments where they were continuously being told that if you are gay there is something wrong with you.”
“Ugh, thank god I didn’t grow up in one of those.” Jenny says while rolling her eyes.
“If you only knew.” Tiffany thinks to herself.
“So then when they grow up and their sexuality develop, it turns out they are attracted to the same gender.” Tiffany continues to explain.
“Exactly.” Jenny says. “It is not something you choose. You are just born that way.”
“But due to their upbringing, these people now think there is something wrong with them.” Tiffany continues. “The only thing that stops them from engaging it is that in some states homosexuality is still looked down upon. But they fear that once it becomes acceptable, they will start engaging in it.”
“So …” Jenny shrugs. “If they are secretly gay they should come out.”
“Which because of their upbringing makes them believe there really is something wrong with them.”
Jenny thinks about it a little and says, “So … what you’re saying is they are people who are gay, but grew up being told gay is bad, and when they discover they are gay they think there is something wrong with them and try to push for anti-gay legislation so they’d have an excuse to not be gay?”
“Pretty much.” Tiffany nods.
Jenny puts one hand on her forehead and says, “Oh my god. Those poor people. They must have lived in **** all their lives.”
Tiffany takes hold of her friend’s hand and says, “Jenny, you’re probably not but … in the event you happen to be struggling with forbidden desires, please don’t keep them for yourself. You can always talk to me about them.”