The business of sperm banks is all about the concepts of supply and demand. What people want the most of is what they have to have in supply. Cyros, an International sperm bank, has reached its capacity of 70 liters from about 14,000 donors. Now, they have a waitlist of donors that is 600 people long.
There are some people that are rejected from being put on the waitlist. Redheads for example are rejected by Cyros because there is a low demand for their sperm internationally. For someone to want a redhead they would have to have either a partner with red hair or have a preference for red hair.
It’s a preference that isn’t very common, with the exception of in Ireland where they have a high demand for redheads. The most common request is for brown-haired, dark-eyed donors. Cyros has many Mediterranean locations that use them as a source.
Having brown hair and dark eyes is common in the Mediterranean, and people tend to prefer children with similar features to their own. For that reason, the darker genetic color combination is in high demand for the company. Alternatively, redheads make up a very small percentage of any population, and therefore are not in demand.