The Celebrity Big Brother star - who already has sons Matthew, 22, and Louis, 11 - is said to have visited the Manchester Fertility Services clinic with Townley last week to discuss IVF treatment.
A friend of Welch's told the Sunday Mirror: "Denise has told me the only problem with the age difference between her and Lincoln is that they can't have kids.
"I know Denise would love to be able to give Lincoln a baby and the challenge of coping with a newborn at her age wouldn't faze her at all.
"But there are all sorts of ways they might be able to do that to make their happiness complete - through IVF, adoption or even surrogacy.
"I know she has a cousin who works in an IVF clinic in Liverpool and it is something she has thought about. Den and Lincoln have a very special bond and are both great parents. So it would be lovely if it happened for them."
Townley, who has a 20-year-old son, is said to be fully supportive of Welch's hopes to have another child, and the pair apparently prefer the option of IVF after a promising meeting with specialists.
They became engaged earlier this year after the breakdown of Welch's marriage to Tim Healy.