She said: "I'm not interested in anyone else's opinion. I am in love with Phil and he's in love with me.
"Soon I'll be holding my son or daughter in my arms and Phil will be the proud dad."
Her lover is the son of Pearl's daughter Lynette Bailey - who she put up for adoption when she was 18-years-old.
When his mother passed away, Phil tracked down his long lost grandmother and they quickly fell in love.
Pearl told New Idea magazine: "From the first moment that I saw him, I knew we would never have a grandmother-grandson relationship.
"For the first time in years I felt sexually alive."
It was during their second week together, after dinner and wine, that Pearl made her move.
"I called Phil into my bedroom, sat him on the bed, and then I leant over and kissed him," she added.
"I expected rejection but instead he kissed me back."
Phil revealed: "I wanted to kiss her there and then. My feelings were overwhelming.
"I love Pearl with all my heart. I've always been attracted to older women and I think Pearl is gorgeous. Now I'm going to be a dad and I can't wait.
"Yes, we get laughed at and bullied when we go out and kiss in public but we don't care. You can't help who you fall for."
The pair paid $54,000 (£35,000) to find a surrogate mother and buy a donor egg to inseminate with Phil's sperm.
They placed an advert asking for an open-minded surrogate, and Roxanne Campbell applied.
"Initially I was shocked," says Roxanne, 30. "But they're a brilliant pair and I saw how much they loved each other. I know the baby will be loved too."
Pearl said: "I am finally going to be a mum and not forced to give up my child. Phil's going to be a great dad.
"I never in a million years thought at 72 I'd be 'pregnant' and in love with my grandson.
"I make no apologies and I believe God's given me a second chance."