The hottest Reproduction Substack posts right now

And their main takeaways
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Top Philosophy Topics

A Problem of Prophesy

David Friedman’s Substack • 260 implied HN points • 20 Dec 25
🔬 Science Reproduction
  1. Total fertility rate (TFR) is a snapshot-based prediction that can underestimate the number of children women will actually have if they postpone births, while completed fertility rate (CFR) is what determines population change.
  2. There is a biological limit to how late people can have children, so shifting births to older ages can only go so far, though advances in reproductive technology could change that limit.
  3. Life expectancy at birth (an estimated measure) is also a prophecy and can fall during temporary mortality shocks even though completed life expectancy will likely be higher if mortality rates continue to decline.

What makes a good egg?

De Novo • 154 implied HN points • 30 Nov 25
🔬 Science Reproduction
  1. For an egg to develop into a healthy baby, it needs to have the right number of chromosomes and be free from harmful mutations. This can be checked using various genetic testing methods.
  2. Eggs must also have proper epigenetics, meaning they need to erase the old marks from the starting cells and replace them with new ones specific to eggs. This part has been tricky for scientists.
  3. Besides genetics and epigenetics, eggs need to be the right size and have enough nutrients and energy sources. To be useful, any method for growing eggs in the lab must make sure the eggs are consistently high-quality and safe.

Opponents of IVF Should Oppose Natural Conception Too

Parrhesia • 647 implied HN points • 02 Mar 24
🏥 Health & Wellness Reproduction
  1. Opponents of IVF may need to extend their beliefs to also include opposition to natural conception, as it results in the loss of embryos similar to IVF.
  2. Banning IVF raises the issue of a paradox where excess embryos are never created nor destroyed, leading to no children being born.
  3. A consistent stance against IVF should logically also entail a stance against natural conception, due to the loss of embryos that often occurs in both processes.

Hanky-Panky in the Sea

Street Smart Naturalist: Explorations of the Urban Kind • 59 implied HN points • 24 Feb 22
🔬 Science Reproduction
  1. Rockfish have a unique way of mating that involves a dance and internal fertilization, which leads to them producing many offspring. Some can even reproduce at over 100 years old!
  2. Geoducks are known for their impressive reproductive abilities, releasing millions of eggs after males eject sperm into the water. They can produce these for over a century as well.
  3. Olympia oysters are hermaphrodites, starting life as males and switching between genders based on their environment. This means they have a different way of reproducing compared to other sea creatures.
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