And it is a point in their lives when they feel they have been in a loving and stable relationship long enough.
The research, by home fertility and pregnancy test company Clearblue, also examined what women felt boosted their chances of becoming pregnant.
According to the survey of 3,000 women, 70pc felt a healthy diet was important to improve their odds of conceiving.
Regular sex (60pc) and giving up alcohol (42pc) would also boost the ability to become pregnant, according to those women polled.
Losing weight (33pc), quitting smoking (31pc), exercising more (25pc) and giving up caffeine (21pc) also figured highly in the list of the best ways to increase the chances of conceiving.
Dr Dawn Harper, who co-presents Channel 4's Embarrassing Bodies series, said: "It is interesting that the survey shows that 29 is a popular age to have a baby.
"Whatever your age, my advice is to stop smoking, cut down on alcohol and maintain a healthy weight before you start trying to conceive."
Singer Christina Aguilera, who had her first baby in January, is 29.
And Oscar winner Natalie Portman had her first baby earlier this month, having just turned 30 the week before.