Like any hard-nosed journalist, Elizabeth Vargas knows if something seems awry. So when the 20/20 coanchor delivered second son Samuel Wyatt Aug. 16 and discovered he had blond hair and blue eyes, "I kept saying, 'Are you sure he's mine?'" she says. "Since both my husband Grammy-winning singer Marc Cohn, 47, and I are dark, we were a little puzzled."

In other ways Samuel is already taking after his older brother Zachary, 3. "Zachary is very tall for his age, and Samuel's also enormous," says Vargas, 44. "He's just over a month and already 12 lbs. I think we're going to have another very big boy here." For now, they have a bit of a colicky boy—"I haven't slept more than 90 minutes at a time in a month," says Vargas—but fortunately Cohn's vocals provide for some comfort. "Marc is trying the songs he's working on for his new CD on the baby," says Vargas, who is expected back at her anchor desk in November. The verdict? Says Vargas: "The mellower ones definitely work better."

SAMUEL WYATT COHN
August 16, 2006
7 lbs. 9 oz.

For more of Elizabeth Vargas on working moms, sibling rivalry and her post-baby body, go to PEOPLE.COM/VARGAS