A new TV advertisement has been aired as Washington State heads closer to a ballot on Referendum 74 on whether to retain equal marriage legislation.

“I’m so proud of my daughter Sarah,” mother Chris Morningstar said in the short TV advertisement. “She and her partner, Cheryl, are just wonderful parents. When Cheryl was diagnosed with brain cancer, my heart just went out to all of them. It really hurts watching them fight this cancer. And what’s just as hard, is watching what they’ve had to go through because they’re not legally married.

“One night in the hospital, Cheryl had a seizure. She was asking for Sarah and no one called. Only marriage guarantees all couples can be there for each other when it really matters.”

Washington’s state legislature passed equal marriage laws earlier this year.

The legislation was due to come into effect in June, but was delayed as opponents submitted more than 200,000 signatures to force the measure through a referendum (R 74) this November.

The anti-equality group Preserve Marriage Washington submitted almost 232,000 signatures for Referendum 74, which is nearly twice the number of required signatures to put the measure to a public vote.

While every state ballot on equal marriage so far undertaken in the US has seen voters block marriage rights for gay couples, the left-leaning think-tank Public Policy Polling said last month that voters in Washington may be the first to approve equal marriage. Their polling indicated 51 percent supported equal marriage, with 42 opposed.

Equal marriage proponents raised nearly $1m in June alone with major donations from Microsoft’s co-founder Bill Gates and CEO Steve Ballmer. In August, the founders of Amazon donated $2.5m to the cause.

iPhone and iPad users may need to click here to access the advertisement