Trevor

I'm not sure exactly what you mean by "challenging his masculinity", but as a man primarily raised by women, without a lot of male role models, he nonetheless absorbs ideas of what he thinks masculinity should look like. As he gets older, he tries to enact different forms of masculinity by trying to make himself physically attractive, pursuing girls, trying to make money, and trying to become popular. He also observes other men and their values, such as when he notices the tension between his mother and stepfather due to Abel wanting a very traditional wife who respects his authority without question. Trevor's vision of what masculinity should look like is shaped by his close bond with his mother and a deepened understanding of how different people can embody masculinity in different ways.