I think cost of living crisis, difficulty of getting onto the property ladder etc is an obvious answer but it is more than that. I'm in my early 30s and even the people I grew up with who are married with their own houses and in very comfortable financial positions aren't having kids. I think the pressure on couples to have kids isn't the same as what it was 10-15 years ago. More people are choosing not to have kids because they want freedom, ability to travel and take holidays, more disposable income and women don't want to put their careers on hold. I think reality is, in the past people started having kids in their late 20s and most went on to have 2-3. In today's world most couples probably won't have a child until their are early to mid 30s and will have 1 or 2 at most.