In A.T.&T. Corp. v. Hulteen, the U.S. Supreme Court held that the employer lawfully calculated pension benefits for employees who took pregnancy disability leave during the 1960s and 1970s. Before the passage of the federal Pregnancy Disability Act in 1979, for the purpose of calculating pension benefits, the employer gave lesser service credit for employees who took pregnancy disability leave than for other types of leave of absence. The court held that the employer's pre-1979 limitation of pension credit for pregnancy leave was lawful at the time, and that the recent Lilly Ledbetter Fair Pay Act did not apply as there was no unlawful act that affected the present pension benefits.