Monica Geller altered the trajectory of the entire series, having life-changing effects on its characters. Summarizing the role of Monica in the series, Martin Gitlin wrote in his book "The Greatest Sitcoms of All Time" that while her friends "were ... just out to make the most of their social lives", Monica "sought to keep the others in line" while searching for "Mr. Right", who surprisingly turns out to be close friend Chandler. Several years before Monica and Chandler became romantically involved, Cox once joked in an interview that if her character were to ever have sex with another main character, it
Monica Geller the crew attempted to conceal Cox's pregnancy using a combination of baggy, loose-fitting costumes and props instead. However, at times the actress' growing belly was still detectable by viewers in spite of the crew's best efforts. At the beginning of season one, Monica is 25 years old. Rita Loiacono of SheKnows Media believes that Monica is the show's most fully realized character from the very beginning of the series because her "quirks were developed to a tee." Like several strong female sitcom characters who were popular throughout the 1980s and 1990s, Monica possesses a natural maternal instinct, constantly "vocalising a