Joel Stringfellow (njyoder) wrote in thequestionclub,
Joel Stringfellow

Why do condoms fail?

With perfect usage, why do condoms still manage to fail? 

This is confusing the fuck out me.

Under perfect usage, they are about 98% effective (source). This figure seems too low for latex--a rather impermeable material.

Unless I've greatly misunderstood things, perfect usage means that a given condom is used once, hasn't been torn/ripped, the right size was used, and was properly put on.  In testing, condoms are filled with 1+ liters of water and stand up to the pressure just fine without leaking.

EDIT: The only thing that makes sense here is that 'perfect use' only refers to humans doing their part correctly, but the condom not being manufactured quite right and breaking. Is this correct? It's not entirely clear what the definition of 'perfect use' is.

Perfect use = humans doing their part correctly, ignoring manufacturing failures.

EDIT 2: Are these stats for perfect usage the probability of pregnancy for SINGLE use, or for use over some period (many studies test over 6 months from that I checked)?

The statistics are for 1-year failure rates.

Even with microscopic tears forming in perfect use, that would only let a miniscule amount of spermatozoa through and an egg needs a good amount of that ejaculate to get through (2ml of ejaculate should have at least 40 million sperm)...with microtears only letting through a small fraction of a percent.  And even with that many sperm from a full ejaculate getting through, people often don't get pregnant on the first try.

Microtears are not a significant factor, like I suspected.

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