News

1. What happens in natural conception

Yes, the vagina, cervix, and uterus have a lot of built-in defenses. These exist to protect against infections — but sperm have to pass through the same gauntlet.

Vaginal acidity → The vagina is acidic (pH ~3.8–4.5) to kill bacteria and fungi. This acidity does kill many sperm almost instantly.

Cervical mucus → Acts like a filter. During most of the cycle, it’s thick and blocks sperm. Around ovulation, it becomes thinner and more “friendly,” but still selective.

Immune system → White blood cells can attack sperm as “foreign” cells.

Structural obstacles → Only a small fraction of sperm (~1 in a million) make it to the fallopian tubes.

So yes — you can think of it as most sperm being “eliminated” before reaching the egg. The survivors are the fastest, most motile, and most resilient. 2. IVF and your “battle pass” analogy

In In Vitro Fertilization (IVF), sperm don’t have to run the full gauntlet — they’re either placed near the egg in a lab dish (classic IVF) or directly injected into the egg (ICSI). So in gamer terms:

Natural conception → 1 million players drop in, only one survives to win.

IVF → The system says, “You’ve already bought VIP access, here’s the final round.”

3. Does bypassing natural selection increase disability risk?

This is where nuance matters:

In natural conception, the weakest sperm usually never reach the egg, so there’s a degree of “natural selection” at the sperm level.

In IVF, especially with ICSI (where one sperm is injected directly), some of that natural selection is bypassed.

Studies show:

Slightly higher risks of some rare genetic or imprinting disorders in IVF/ICSI babies (e.g., Beckwith–Wiedemann, Angelman syndrome).

Slightly higher rates of preterm birth and low birth weight.

However, most IVF babies are healthy, and the increased risk is small in absolute terms.

Many scientists think that these risks come more from underlying infertility issues in the parents rather than IVF itself. In other words, if someone’s sperm or eggs already have higher risk factors, IVF isn’t creating them — it’s just making fertilization possible despite them.

✅ In short:

Yes, the vagina does “kill” most sperm — that’s natural selection.

IVF does skip a lot of that process — kind of like paying for early access in a game.

There is a small increase in certain risks, but the vast majority of IVF babies are healthy