I'm not sure if you cited that because it's the first to come up in a web search but the fact that "undecided" was not an option is a red flag in my mind.
What do you think of this one:
https://www.pewresearch.org/short-reads/2024/02/15/among-you...
"When asked about having children, 51% of young adults who are not parents say they would like to have children one day. Three-in-ten say they’re not sure, and 18% say they don’t want to have children."
In other words, imagine if 70% of people that want to have children have had at least one child by the age of 34. So we start with e.g. 100 people where 6 don't want to have children (appealing to the 94/6 ratio from the older study). Then we remove 70% of the 94 that do and we're left with 28 that do and 6 that don't, so now the 'don't want' group make up 18% of the total sample. And I think 70% of people that want to have children, having had at least one child by 34, is a very reasonable ballpark.
Check out the questions [2] they asked, in the study you linked, and you can see that you end up with a highly unrepresentative sample of society: 33% live with their parents, 19% are unemployed, 44% receive financial assistance from their parents, and they're democrat:republican at a near 2:1 ratio.
[1] - https://news.gallup.com/file/poll/164630/Fertility_130925.pd...
[2] - https://www.pewresearch.org/social-trends/wp-content/uploads...
I will day that I'm struggling to align these survey questions with human nature as I understand it.
I have a friend who "wants kids" and two different women, when they reached a certain age in their 30s, signaled they wanted to marry him and have kids.
But they both exhibited red flags that caused him to decline. One woman didn't act like she liked him, even though she was also saying she wanted to settle down together.
The other woman was unwilling to discuss how they'd raise the children given the fact they were from different religious backgrounds.
Given he's now in his 40s he'll likely never have kids.
I suppose if he was super passionate about kids he'd enter an unhappy marriage and make sure he got some kids out of it, before possibly ending up divorced.
So wanting children was more a conditional thing than a binary thing, and I don't know if these surveys can capture that.
And for women this is particularly true. Because in practical terms you're going to have at least a couple of years between kids. At the minimum this is because their cycle is suppressed while breast feeding, and then it generally takes a number of months to get pregnant, even moreso if somebody is in their 30s, let alone 40s. And so if you want to have 3 kids, it's a practical necessity to start very early - that's pushing towards a decade of time.
So modern society is really rather a lie in this regard, and I think that's been quite harmful. Because this lie is encouraging all of us (male and female alike), to push parenthood out later and later. And that dramatically increases the odds that 'later' eventually becomes never.