News that an uninsured transgender woman in Colorado was denied a free mammogram has prompted two advocacy groups to petition the federal government for equality in screening. “That is irrational discrimination, plain and simple,” said Harper Jean Tobin, director of policy for the National Center for Transgender Equality. “Breast-cancer screenings save lives and should be available to all women, period,” added Shane Snowdon, director of the Human Rights Campaign’s health and aging program. President Obama’s 2010 Affordable Care Act prohibits discrimination “on the basis of sex, including on the basis of gender identity or sex stereotyping,” they wrote Friday in...