How to Bank Sperm

Published 2026-04-22 • Original post

Day 21/30 of posting daily

If you are assigned male at birth, then for various reasons, you may want to do gamete storage. Having kids is one aspect on which people have a relatively reasonable chance of changing their minds about as they get older, so it can be worth preserving optionality by storing gametes sooner.

If storing male gametes (sperm), it is typically not as pressing and urgent to bank them ASAP as with female gametes (eggs), but there are plausibly minor benefits to banking sooner in the base case (risk aversion), and if you are reading this, then there are various medicines and treatments that can interfere with sperm production (gametogenesis), including both feminizing HRT (anti-androgens) and some masculinizing HRT (eg: exogenous testosterone or anabolic steroids). This is often reversible, which I will discuss later.

I will discuss briefly how gametogenesis works, what factors to consider before doing storage, and briefly what the process looks like

Sperm Creation / Spermatogenesis and Heat Exposure

The sperm creation cycle takes about 74 days from start to completion, and occurs within the scrotum. This process is very heat-sensitive, and so the scrotum is typically kept at a lower temperature, about 2-4°C below body. Too much heat in some parts of the process leads to apoptosis (when cells die voluntarily).

Eg, from a paper:

A short exposure of the testes to heat by immersing the scrotum in a hot water bath at 43 °C for 15–20 min also results in germ cell apoptosis

The amount of apoptosis depends on how hot it is, and also how long the exposure is. If you are storing, you want to avoid heat as much as possible. This includes avoiding saunas and hot-tubs, but also generally avoiding being outside in very hot weather. There are small but measurable reductions in birth rates in national statistical following particularly hot days / heat waves.

If you have any medications that are contraindicated with sperm storage / conception, then you should avoid them, the washout period depends on what drug, sometimes it’s a short time, but other times it can be for the whole 75 day period.

Quality Metrics

There are a few metrics people use as a proxy of sperm quality, and the WHO guidelines on what is acceptable (though clinics may have different thresholds)

• volume (>1.4 mL)

• conc. of sperm (>16M)

• progressive/total motility (% that move) (>30% and >42%)

• morphology (most vibes-based and doesn’t matter as much, but >4% is “good”)

You can also measure other metrics, but they cost more money. If you want to consider an additional one, you could look at:

• DNA fragmentation (how much of the DNA is damaged)

the exact measurements that are good that differ between clinics, but there is typically a minimum threshold they need for each of these to consider banking.

Measurements can also differ substantially between samples.

Things that affect metrics

The main thing, as mentioned before, is to avoid heat.

A main supplement you may want to consider, is a moderate dose of Zinc. This has been shown to often increase volume so you get more stored per session.

Being generally healthy and active and avoiding alcohol helps.

Some others from wikipedia:

Dietary deficiencies (such as vitamins B, E and A), anabolic steroids, metals (cadmium and lead), x-ray exposure, dioxin, alcohol, and infectious diseases will also adversely affect the rate of spermatogenesis.

If you are not currently on any medical regimen, then it’s not that expensive to test the main metrics, though it is somewhat annoying. I will discuss the process in a later section

Can you restart spermatogenesis again post-HRT?

Most HRT regimens causes spermatogenesis to be greatly reduced or stopped. People used to believe this might be permanent, but there is a small study with 9 transgender women, who stopped HRT who all could later produce sperm again.

The majority were producing sperm within about 7 months or sooner, but some took more than a year

And though the evidence is in favor, it is also is not guaranteed that it will work. You can consider yourself whether you would find it more mentally painful to delay transition by some time, or to see yourself re-masculinize at some later point in time

If you started HRT at a very young age before the testes were fully developed, it’s unclear whether it’s possible to induce spermatogenesis later post puberty. It’s highly uncertain, but plausible that it might take years, or it might not be possible at all. There is not research in this direction

Storage Process

Generally, the process for gamete storage looks like this:

• Find a place that offers sperm storage, most typically this will be an IVF clinic that happens to also offer sperm storage. In this case, you probably want to see how good their IVF success rates are, but it is also usually possible to ship gametes between clinics. (Cross-country this can be more difficult though, check restrictions)

• Make an appointment with them

• You will need to do some tests before you do storage. This means typically producing a sperm sample, as well as a blood/urine test to see if there are any STIs (depending on the clinic, they may reject you, or they may just need to handle the sample differently)

• Producing a sample involves abstaining1 for about 2-7 days, but depends on the clinic. A period of 2-3 days is considered around optimal, you don’t want it to be too short or too long.

• Depending on your quality and volume, you probably want to produce at least 2-3 samples to be stored.

• It is possible to directly store embryos if you already have a partner and they are willing to store embryos at the same time

Then after this, they will be split up into multiple “straws” per sample, placed in a cryoprotective fluid, and stored under liquid nitrogen temperatures (-196°C) for as long as you are willing to pay them, and for as long as the laws in your jurisdiction allow.

In many places, it is also alternatively possible to extract gametes surgically if you are unable to produce samples otherwise, or if parameters

Depending on where you live, it may be easier to leave your country and store them in a neighboring country where situation can sometimes be more favorable.

Post-Freezing

After freezing the sperm, it’s worth noting that that there will be some degradation in quality from the process of freezing them, this is partially why there are minimum standards to freezing.

Depending on how much you stored, different procedures can be more or less viable.

The lowest-cost procedure is to do IUI (intra-utary insemenation) which involves directly inserting sperm into a womb after inducing an ovulation cycle. This requires the most amount of sample

If you have less to work with, IVF or ICSI done with extracted eggs is more sample-efficient.

It’s also worth considering the legalities with gamete storage. Some countries only allow storage for a very limited time. Some don’t make it easy to transfer samples abroad. Some have different rules on what happens after death. Some places have special restrictions if you want the option of surrogacy. You should probably look into these questions for your country.

Closing

I may try to provide some anecdotal examples of what this process looks like at a later point.