By the 1970s, the Women’s Rights Movement in the United States achieved significant legislative victories, which were pivotal in advancing gender equality. One of the critical outcomes was the introduction of the Equal Rights Amendment (ERA). Although this amendment aimed to ensure that rights cannot be denied based on sex, it faced considerable opposition and was not ratified by the necessary number of states. In this context, which of the following best explains a prominent argument made by opponents of the ERA during this period?