HERE we go again.

For the second time in a year, a childless, unmarried woman in her 50s has been nominated to be a justice on the Supreme Court and the critics have come out swinging. This time Elena Kagan, the former dean of Harvard’s law school, who is now solicitor general, has been described as having sacrificed a home and personal life in her quest for a brilliant legal career.

It all sounds eerily like when Sonia Sotomayor, who is 55 and single after a brief marriage when she was younger, was appointed to the Supreme Court last August and had to deflect suggestions that she treated colleagues and close friends like an extended family because she had no children of her own. Deborah Rhode, director of the Center on the Legal Profession at Stanford Law School, said such stereotypes are unfair but common given society’s double standard when it comes to single women and work.

She said she got a phone call last week from a reporter questioning whether Ms. Kagan was equipped to rule on workplace issues considering that she had never had children. “I didn’t think you needed to actually be a mother to appreciate the challenges facing working mothers,” Ms. Rhode said she told the reporter. “I do think it is a step back if we start to penalize women for not making the conventional choice.”

Besides, Ms. Rhode added: “I resist the notion that the only way to be happy in the world is you have to be married. We want a world where people can make a variety of choices and be happy.”