Abby Stein discovered what the word "transgender" meant — and that the term accurately described her — when she snuck on the internet for the very first time back in 2011, in a mall bathroom, at the age of 20.

“The first thing I searched was whether a boy could turn into a girl in Hebrew — I didn’t speak English at all — and that led me to the first Hebrew Wikipedia page that was talking about transgender,” Stein told NBC’s "Today" show Tuesday. “It was the first time I heard that term. I identified as such without having words for it.”

Stein is thought to be the first openly transgender woman raised in a Hasidic community, an experience she chronicles in her memoir, “Becoming Eve: My Journey from Ultra-Orthodox Rabbi to Transgender Woman,” which was released Nov. 12. Though Stein said she always felt different and was not interested in playing with boys when she was younger, she felt pressured to keep her identity secret and follow the more traditional path of living as a man, getting married and becoming a rabbi.

“For me, personally, there were a lot of expectations because of my family,” Stein told "Today."

Yet, Stein was inspired to start breaking free from those expectations in 2011 after she found out that she and her now ex-wife were expecting a child.

“How could I raise someone, bring someone into the world if I don’t know who I am?” Stein said.

Shortly after her son was born, Stein took a friend’s tablet to a mall bathroom on multiple occasions for research — as Hasidic leaders limit members’ web and smartphone use — and came out as trans shortly after. Stein's father was not receptive to the news, but Stein felt she had somewhat of a breakthrough after her father admitted trans people exist, something she said “was not a given for an ultra-Orthodox rabbi.” A retelling of their two-hour conversation serves as the epilogue of “Becoming Eve.”

“It taught me a lot about bigotry and transphobia in so-called religious communities,” Stein said. “I realized it’s usually not religion, and it’s not God. It’s people and the culture, which is why it was a big deal for my dad.”

Stein said she was shunned upon leaving the Hasidic community in 2012 even before she publicly came out as trans, but Judaism still plays an important role in her life. She regularly gives speeches to Jewish people and is a leader in New York City’s Jewish activist community. When she first became involved in activism, one of her goals included wanting the Hasidic community to “become transphobic — because that would mean they recognize we exist.”

“I can say three and a half years later, mission accomplished. The Hasidic community is officially transphobic, which didn’t exist growing up, but at least now they talk about it,” Stein told "Today."

“At the end of the day, I am who I am today, of which I am very proud and happy and comfortable, because of the sum total of my experiences,” she said.

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