More than three quarters of Irish adults have no idea what age their fertility will start to decline.
A new national study has also discovered that more than half of us think our fertility will start to decrease at 35, that is five years after it actually does.
Health website myfertilitycheck.ie spoke to almost a thousand people between the ages of 25 and 44, after it was revealed that Irish mothers are among the oldest in Europe.
46% of women say they are waiting for the right partner before they have a baby, while 37% of men claim financial concerns are making them put off fatherhood.
Head of Clinical Services at My Fertility Check, Mary McAuliffe, said: "I see so many women and couples attending for fertility treatment and IVF who are surprised that it has proven so difficult to have a baby naturally.
"A substantial portion of adults think fertility declines at a much later age than it does in reality. 41% of people think the decline begins at 35 while one third believe it starts later - at 40 years."
She said this was a concern.
She said: "The results really highlight the need for a nationwide, State-funded education campaign on fertility and reproductive health, particularly targeting students at third level.
Young people need to be educated on the lifestyle choices that can affect their fertility; in particular, age, smoking, alcohol and health issues such as sexually transmitted diseases."
Here are the basic numbers:
* National survey reveals 79% of adults do not know the age at which fertility declines
* 41% incorrectly believe that fertility starts to decline at 35 years
* 46% of women say waiting for the right partner is the primary reason to delay having a baby
* 37% of men say finances is their main reason to put off fatherhood
* 710 men and women aged between 25 and 44 took part in the study