The Radio 1 presenter, 33, and 38-year-old husband Jesse Wood welcomed Rex in February 2013 and, while she would love another, she hopes her children aren't as much of handful as she was.
Speaking to the Sunday People, Fearne said: "Another child would be a blessing. We'll let nature take control and see what happens.
"In my early 20s I definitely put my mum through it. I pushed boundaries and had questionable boyfriends.
"When I was going out loads and going to gigs I probably wasn't telling her where I was. At times she didn't even know if I was in the country. I imagine I caused alarm then. You don't realise that until you're a parent."
When discussing the possibility of her appearing on Strictly Come Dancing, Fearne insisted she would never dismiss the idea.
She continued: "Never say never. I'd love to do some dancing. I'd prefer to present it.
"I've danced since the age of four and thought I'd be a dancer. But I've always wanted to be a mum since I started feeling broody in my early 20s. It's the best thing that has happened to me. The love is off the scale."