Ericsson Method
Last reviewed 2026-10-27
The Ericsson method layers sperm over a column of human serum albumin on the theory that Y-bearing sperm swim down through it faster and can be collected separately. It is cheap, decades old, needs no specialist equipment, and is still offered — and attempts to confirm that the separated fractions are genuinely enriched have not produced a consistent result. It is best treated as close to chance.
The theory
Developed by Ronald Ericsson in the 1970s, the method rests on the proposition that Y-bearing sperm are smaller and faster swimmers than X-bearing sperm. A semen sample is placed on top of a column of albumin solution of increasing concentration; after a set time, sperm collected from the lower layers are said to be enriched for Y, while those that stay higher are said to be enriched for X. The enriched fraction is used for IUI.
Why it is still sold
Three reasons, none of them evidential. It is inexpensive compared with IVF. It requires only ordinary andrology-laboratory equipment, so any clinic can offer it. And because its claimed success rates are in the region of 70–80%, every patient who gets the sex they wanted — which would be about half of them on chance alone — becomes a testimonial.
What the evidence shows
The difficulty is basic and has never been resolved: when independent groups have tried to confirm that the fractions produced by albumin separation actually differ in the proportion of X- and Y-bearing sperm, the results have not held together. Some found no meaningful separation at all. Unlike flow cytometry, where the instrument measures the DNA difference directly and the mechanism is not in dispute, the albumin gradient relies on a swimming-speed difference whose existence is itself contested.
Note what is being claimed and what is being measured. Flow cytometry measures DNA content, which genuinely differs between X and Y sperm. The albumin method infers sex from motility, which is a proxy at best. That is the whole difference between a weak method and an unsupported one.
What to ask if a clinic offers it
- What proportion of your patients using this method had a child of the sex they selected? Not the laboratory enrichment figure — the births.
- Over how many patients, and across what period?
- Is that your clinic's own data, or the figure supplied by whoever licensed you the method?
- What is the pregnancy rate per IUI cycle here, for my age? (Because that, not the sorting, usually decides the bill.)
A clinic with real outcome data for this method would be unusual and worth listening to. A clinic that offers a percentage and cannot say whose patients it describes is quoting marketing.
How does the Ericsson method work?
Sperm are layered over a column of human serum albumin. The claim is that Y-bearing sperm pass through faster and can be collected from the lower layers, producing a sample enriched for one sex, which is then used for intrauterine insemination.
Is the Ericsson method accurate?
The evidence does not support the figures usually quoted. Independent attempts to confirm that the fractions are genuinely enriched have not produced consistent results, and the method is best treated as close to chance.
Is the Ericsson method better than MicroSort?
No. Flow cytometry measures the DNA difference between X and Y sperm directly; the albumin method infers sex from swimming speed, a proxy whose existence is disputed.
How much does the Ericsson method cost?
It is substantially cheaper than IVF because it needs no specialist equipment, which is a large part of why it is still offered. The relevant comparison is cost per child of the sex you wanted, not cost per attempt.
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