Nordisk Cryobank, a leading European sperm bank, has unveiled a curious new rolling billboard in the shape of its Sperm Bullitt which has been popping up on cycle paths throughout Copenhagen.

CEO Peter Bower, who rides the bike, said its design leads to him constantly being stopped by curious passers-by, adding: "we're always looking for new donors so it's a fine bonus that the Sperm Cell Bike gets people’s attention."

The bike also acts as an environmentally-friendly alternative for the sperm bank to transport its samples to fertility clinics around Greater Copenhagen.

Bower commented: "The first idea was how we could deliver to the fertility clinics in a C02-friendly way. Shortly afterwards followed the idea of a custom-designed bike with a cooling system. Now, six months later, we can cycle around the city on our sperm cell bike."