Updated at 3:15 p.m. with comment from Cantwell's campaign:

WASHINGTON -- Turning a highly politicized issue personal, Sen. Maria Cantwell's Republican challenger criticized her support for making Plan B emergency contraceptives widely available to younger teen girls, noting that Cantwell is unmarried and saying she has frequently voted to "undermine the role of parents in child rearing."

In an email to supporters Thursday, State Sen. Michale Baumgartner, a Spokane freshman, said Cantwell's position on the so-called "morning after pill" shows her to be an extreme liberal who is left of most Washington voters.

“Cantwell is so extreme that she doesn’t see anything wrong with 11 year-old girls getting Plan B without a prescription,” Baumgartner wrote.

This week, Cantwell joined Sen. Patty Murray and 12 other Senate Democrats in signing a letter to U.S. Department of Health and Human Services Secretary Kathleen Sebelius asking for scientific justification for her decision to overule the Food and Drug Administration's call to make Plan B available behind pharmacy counters to girls 16 and younger.

The FDA has determined that the pills work and are safe. Sebelius and President Obama have portrayed Sebelius' decision as based on judgment calls about the maturity of preteens and younger teens to use the pills appropriately. Plan B is available without prescription for those 17 and older.

Baumgartner, who has a 6-month-old son, said he mentioned Cantwell's marital status to contrast her position with Obama's. The president referred to his two daughters in explaining his support for Sebelius's decision, which has dismayed women's rights advocates and health-care professionals.

Baumgartner said requiring younger girls to get prescriptions for Plan B would make it more likely they would receive counseling from an adult.

Rose Kapolczynski, Cantwell's campaign consultant, said in an email:

"Maria Cantwell believes that the Plan B decision should be based on the best available science. Washington voters support protecting women's health. You don't need to be married to know that Baumgartner's anti-choice position is out of touch."

Elaine Rose, chief executive of Planned Parenthood Votes Northwest, said Cantwell is right to support making Plan B more widely available. Rose noted that half of pregnancies in the United States are unplanned, and the country has one of the highest teenage pregnancy rates among developed nations.

When girls who think they might be pregnant can't or won't talk to their parents or health-care providers, Rose said, ready access to Plan B can prevent unwanted births.

"We should be doing all we can to help young girls from becoming parents before they are ready," Rose said.