Did a giant sperm called Stan buy your morning coffee? Perhaps he held a door open for you, gave you flowers, or hailed a taxi?

You may see one of these situations playing out in Martin Place this week. A friendly, lycra-suited sperm named Stan has been swimming the streets of Sydney, doing good deeds and urging others to do one, too.

Within Australia, demand for donor sperm is currently outstripping supply, causing many people to import sperm from overseas. In an effort to get Australian men to come out and bat for someone else’s team, fertility company Genea has launched Stan the Sperm on an unsuspecting public.

“We’ve had some really great reactions out on the street. Lots of people have been doing double takes when they realise what we’re promoting. One man come up to us to say ‘I’ve got a beard so I should have good sperm,’” says Genea Fertility’s Nicole Papoutsis.

In Australia, one in six couples struggle to conceive at some stage in their relationship. “Sperm is in such high demand, especially amongst lesbian couples, single mums or couples who are having trouble conceiving,” Papoutsis says.

Stan the Sperm will be hanging out in the CBD for the next two weeks. If you’re a healthy male and interested in becoming a sperm donor, or know someone who is, visit genea.com.