"Right now, he's not letting me sing anything to him," she told PEOPLE Wednesday in Washington, D.C. "He is so interested in putting the neck of the guitar into his mouth, it's difficult to play."
The 46-year-old singer was in town to testify before a congressional panel about the Breast Cancer and Environmental Research Act.
"I want to know what causes this disease – for me, and for the 2.3 million others who share this diagnosis," said Crow – who was diagnosed with breast cancer in 2006 – speaking on behalf of the National Breast Cancer Coalition. "We need more resources to figure out what the environment has to do with [it]."
On the Road AgainAs for her own health, Crow – who kicks off her summer tour in July – tells PEOPLE: "I'm great, as far as I know. I believe I'm cured. I'm really the poster child for early detection."
As usual , Wyatt, 1 – whose recent accomplishments include learning to walk and eating grown-up food – will accompany mom on the road.
"He's been doing it since he was two months old," said Crow, who adopted Wyatt when he was two weeks old. "He's been around the world. He's really the rock star – and I'm his side kick now."
There are possible signs of dissension within the family, though. "I have said I'm a [Barack] Obama supporter. But every time Hillary [Clinton] comes on TV, he's just standing there and clapping," she explained. "So we may have differing political platforms. It's funny. But it's very sweet."