>>> to a decision by the world's largest sperm bank to turn away potential donors. there is a report that red heads are no longer welcome. nbc's stephanie gosk is in copenhagen with the details on this. good morning to you.

>> reporter: good morning, matt. the poor red heads . they're always getting picked on. most of the time unfairly. we went to check out this report. we went to this largest sperm bank in the world. red heads are getting turned away but actually all scandinavians are being turned away because for the first time this sperm bank has a supply glut. a thousand years ago maurading hordes of vikings from scandinavia conquered europe spreading their legacy and their genes. today they are back at it now less violently with the help of the denmark based cryos, the largest sperm bank in the world.

>> we started in a small place.

>> business has boomed.

>> yes. it became bigger and bigger.

>> reporter: 30 years ago he says he had a dream, a strange one, about this -- frozen sperm. they now have 500 sperm donors, ship to 65 countries, and are responsible for nearly 20,000 pregnancies. efficiency and quality control are key. this biotechnician is counting by hand what she calls the super athletic sperm.

>> super athletic is basically just another way of saying a really good swimmer.

>> it's a very, very good swimmer.

>> reporter: the business grew fast but it has also changed fast leading to a surprising development for cryos. they have too much supply. scandinavian donors like this student are no longer needed especially one particular group.

>> we shouldn't have too many red head donors in the stock and we can't take any more for the time being .

>> sorry, prince harry . you need not apply. part of the problem is new legislation on sperm imports around the world, including the u.s., which bans sperm imports from europe because of mad cow disease . but women also have new demands that often go well beyond just height, eyes, and hair.

>> at some point there's going to be the question of, like, how did you choose? and you want to be able to say, i chose the nicest person i could find.

>> reporter: sperm banks like cryos now provide detailed profiles of their donors including voice recordings.

>> i hope my donation can help anyone.

>> reporter: cryos is expanding, hoping to become a network of sperm banks around the world and mix up the donor supply. viking sperm just isn't enough. for this healthy, bouncing, baby business it's time to diversify. the director of cryos says he is always doing what he can to stay ahead of the competition. he says that they are developing right now what he calls the virtual date, dinner and possibly a dance with the sperm donor . sadly, that wasn't available for us to see though we did ask.

>> so many lines, stephanie. thank you very much. appreciate it.