Why was a female character added to the toy story franchise?

The only verified sources supplied discuss the list of characters in the Toy Story franchise and its various media, but they do not mention any rationale or decision-making process behind the introduction of female characters. Without additional documentation or statements from the studio, creators, or cast, we cannot determine the intent or motivation for adding a female character to the series. Therefore, based solely on the evidence given, there is no answer to the question.