[10] After her older sister Cindy began boxing training intending to lose weight by attending the gym of her husband Jordan Maldonado, the 12-year old Serrano accompanied her there.

[10] Initially Serrano was not as interested in the sport, not even attending a family event to watch the Oscar De La Hoya vs. Félix Trinidad fight, but she was an avid follower of Cindy's career and developed a passion for it as she grew older.

[10] Cindy, knowing that she had already been frustrated during a previous sparring session against a boy, intended to dissuade her by stepping into the ring but the younger sister proved that she could defend herself competently.

[11] Admittedly shy, Serrano choose to continue in Maldonado's small gym in Queens with him as trainer, so that the flow of people was controlled and she could focus on her training.

[16] On September 10, 2011, Serrano defeated WIBF Inter-Continental lightweight champion Kimberly Connor via second-round technical-knockout (TKO), for the vacant IBF super featherweight title.

Already a three division champion, she moved back down to the junior featherweight limit to tie Miguel Cotto's record and become only the second Puerto Rican boxer, male or female, to win world titles in four weight classes.

[23] On September 8, 2018, the Brooklyn-based hitter moved up an unprecedented five weight classes to defeat Yamilia Esther Reynoso via tenth round unanimous decision (UD), and captured the WBO light welterweight.

[25] On March 25, 2021, Serrano KO'd Daniela Bermudez with a body punch in round nine at Plaza del Quinto Centenario, San Juan, Puerto Rico.

[33] However, on February 28, Serrano withdrew due to an injury she had sustained during training camp and Taylor fought undisputed light-welterweight champion Chantelle Cameron instead.

Serrano resumed normal service on Saturday, responding to her second professional defeat earlier this year by picking up another world title with a unanimous-decision win.

[36] Serrano faced WBA champion Erika Cruz on February 4 at Hulu Theatre in Manhattan, in an undisputed showdown for all four major world titles in the featherweight division.

[37] In the first defense of her undisputed featherweight titles, Serrano rematched Heather Hardy in the co-main event of the Jake Paul vs. Nate Diaz card on August 5, 2023.

He has cited studies and safety issues and the week prior to the fight told the BBC he was "praying that there will be no mishap or injury due to this deeply misguided and mistaken initiative.

"[41] On December 5, 2023, Serrano vacated the WBC title due to their refusal to sanction future female boxing matches at her desired twelve, three-minute rounds.

[43] However, the fight was cancelled at the last minute, after Serrano was declared "medically unfit" by the Puerto Rican Boxing Commission due to an eye injury.

[44] Serrano faced Stevie Morgan at the Amalie Arena in Tampa, FL on the Jake Paul vs. Mike Perry event on July 20, 2024.

[53] The idea emerged after she participated in the filming of Fight Valley along her sister, meeting Miesha Tate, Holly Holm, and Cristiane Justino and learned of the lifestyle that they could afford.

[10] When queried about the matter, Serrano expressed additional motivation due to the absence of a Puerto Rican female fighter in Ultimate Fighting Championship (UFC) at the moment.

Towards this goal, she continued training in kickboxing under former world champion Luis Ruiz and incorporated Brazilian jiujitsu working with brown belt Gabriel Marte at the Dojo NYC.

[56][57] On July 31, 2015, Ronda Rousey's trainer, Edmond Tarverdyan, expressed the belief that his fighter "can win the boxing world title" while discussing a potential fight with Justino.

Her opponents cannot box and it's easy to look great, but when facing a high quality boxer with punching power as myself, believe me, things are gonna change.

[62] This training was put to the test on August 18, 2018, when she won gold in her first career jiu jitsu tournament, a Grappling Industries event held at New York where she gathered four submissions.

[66] Serrano was scheduled to headline her third MMA event (tentatively another fight with Dahiana Santana, making her debut), this one in Puerto Rico, on January 25, 2020.

[73] At the same time that she made her involvement in MMA public, an interest in potentially joining WWE, noted in 2019, Serrano revealed that she had been training under Jonathan Figueroa (known by his ring name Amazing Red) to become a professional wrestler and that she would be performing for a promotion soon.