Rego gave up working with collage in the late 1970s, and began using pastels as a medium in the early 90s. She continues to use pastels to this day, almost to the exclusion of oil paint. Among the most notable works made in pastel are in her "Dog Women" series, in which women are shown sitting, squatting, scratching and generally behaving as if they were dogs. This antithesis of what is considered feminine behaviour, and many of her other works in which there appears to be either the threat of female violence or its actual manifestation, have caused Rego to be associated with feminism. She has acknowledged reading at a young age Simone de Beauvoir's "The Second Sex", a key feminist text, and that this made a deep impression on her. Her work also seems to chime with the interest in Freudian criticism shown by feminist writers on art in the 1990s, such as Griselda Pollock, with works such as "Girl Lifting up her Skirt to a Dog" of 1986 and "Two Girls and a Dog" of 1987 appearing to have disturbing sexual undertones. However, Rego has been known to rebuke critics who read too much sexual content into her work. Another explanation for Rego's depiction of women as unfeminine, animalistic or brutal beings is that this reflects the physical reality of women as human beings in the physical world, rather than the idealised female type in the minds of men.