Also, women's overall fertility drops off a cliff after 30, but this is downplayed because the extreme sensitivity of the issue.
Now contraception has decoupled these things. You can have the relationship you want, and put off children until "sufficient" economic conditions have been reached.
(It is good news that India is at or below replacement rate! The conversation would be very different if in a few decades time India had to find twice as much food and oil!)
I think it's probably a wise thing to advise against having children you can't afford to take care of. I don't think it was something that was explicitly hammered into me or my peers growing up, but we all saw enough examples of kids being raised in poverty to know that we wanted something better for our own children.
(Even when it's not affecting everyone at the same time, isn't it a form of eugenics? Who decides which individuals can afford children? It's not the individuals.)
However, men do have a biological clock and that clock is simply that they are proxied to women's clocks. Mick Jagger can get a young girlfriend and have babies in his old age because he is famous with lots of money. The typical man cannot do this and should not plan on being able to do this. The data tells us that if a man reaches 45 without children, it is extremely unlikely that he will ever have kids, even if his sperm tests perfectly in the lab.
- likelihood to get pregnant
- likelihood to bring child to term
- health risk to mother during pregnancy and child birth
- health risk to baby during pregnancy and child birth
- increased likelihood of multiple birth defects
- increased likelihood of genetic abnormalities
I'm not casting aspersions. My wife and I had kids when she was 38 and 40 respectively. But, the numbers for the risks are stark.
Kids is fast.
- Stress on the relationship of trying and failing for a long time - Stress of fertility treatments, if needed - Likelihood of dealing with inevitable miscarriages on the way to a birth - Overall "medicalization" of pregnancy in middle age, and the stress of all that contact with the medical system
None of this touches on industrialization and higher education, which seem to be the more universal effects, even if one of their bigger effects is merely to delay motherhood.
Even above age 35, 85% of men are able to conceive within 12 months: https://pmc.ncbi.nlm.nih.gov/articles/PMC11026002/
Like it or not, fertility decline is substantially different between the sexes.
There are trade-offs everywhere.
Men's too, from 40s up. Not as severe, and not cliff-like in the end like menopause. But it compounds, as the typical couple ages are directly correlated.