A young couple reacts with joy at hearing that they are “having a lesbian” baby in a new Australian campaign to promote the legalization of gay marriage.

In the ad, the couple is asked during an ultrasound appointment whether they want to know what they've having.

“We would,” the woman says.

“You're having a lesbian,” the technician tells the couple.

The couple smiles broadly at the news.

“Any child can be born gay,” a caption reads. “So marriage equality is every family's issue.” (The video is embedded on this page. Visit our video library for more videos.)

Shelley Argent, spokeswoman for Parents and Friends of Lesbian and Gays, told news.com.au that the campaign aimed to increase awareness that being gay is not a choice.

An accompanying billboard in Queensland shows a smiling pregnant woman under the headline, “Congratulations, you're having a lesbian.”

The campaign is “designed to get people thinking, and challenge them a little,” said campaign creator Steve Minon. “We're trying to point out to any family that marriage equality can be your number one priority, without your knowing about it.”

(Related: Australian Senate to consider recognizing overseas gay marriages.)