News in 5: 'Disgraceful' anti-gay marriage ad; Katy Perry sued; Trump on North Korea.

1. First anti-gay marriage ad uses mothers to push the ‘no’ vote, labelled “disgraceful”.

Two prestigious Catholic schools have spoken out in defence of gay marriage, arguing the sacrament must evolve with the times, in the wake of the first 'no' advertisement airing on television on Tuesday night.

The advertising campaign, led by the Coalition of Marriage, claims "parents have lost their right to choose". It features Australian mothers telling the camera their "son could wear a dress next year if he felt like it" and that "kids in Year 7 are being asked to role play being a same-sex relationship".

The rectors of Melbourne's Xavier College and Sydney's Saint Ignatius' College, whose alumni include Opposition Leader Bill Shorten and former prime minister Tony Abbott respectively, have written to parents and staff arguing the Catholic Church's understanding of marriage stretches beyond procreation.

"In my experience, there is almost total unanimity amongst the young in favour of same-sex marriage, and arguments against it have almost no impact on them," Xavier College rector, Father Chris Middleton, wrote in the school newsletter.

Father Ross Jones of Saint Ignatius' College argues same-sex couples want to commit to each other for the same reasons as heterosexual couples, "by reflecting on experience and on what it is to be human, using their God-given reason".

Mr Shorten has told Fairfax Media the ad is "offensive and hurtful to LGBTI Australians and their families", AAP reports. And Equality Campaign executive director Tiernan Brady told News Corp Australia the "ad is disgraceful in its dishonesty".

2. Katy Perry being sued by a former stagehand whose toe was amputated.

Katy Perry is being sued by a former stagehand who is alleging she was injured on Perry's 2014 Prismatic Tour and ended up losing the big toe on her right foot as a result.

According to TMZ, Christina Fish was working at one of Perry's concerts in North Carolina in the US and was asked to help move a wall, which rolled over her foot. She said she felt her shoe fill with blood and alleged that, though the production company offered ice, no one called and ambulance and she had to ask a friend to drive her to the hospital.

Her toe was reportedly amputated after contracting gangrene and she is suing for damages - she says she wasn't able to use her foot for months - as well as emotional distress.

3. "All options are on the table." Donald Trump warns on North Korea.

President Donald Trump warned "all options are on the table" as the United States considers its response to North Korea's firing of a ballistic missile over northern Japan's Hokkaido island into the sea early in the Asian day.

The missile North Korea fired over Japan was likely an intermediate-range ballistic missile, with a range of between 1500 and 3000 nautical miles (2778 km to 5556 km).

The Pentagon said that diplomacy was still the preferred option but US Ambassador to the United Nations Nikki Haley said North Korea's action was "absolutely unacceptable and irresponsible" and the Security Council now needed to take serious action, AAP reports.

"No country should have missiles flying over them like those 130 million people in Japan. It's unacceptable," Haley told reporters. North Korea has "violated every single UN Security Council resolution that we've had and so I think something serious has to happen".

4. Comprehensive evaluation backs safety of four-in-one MMRV vaccine for toddlers.

A comprehensive evaluation of the four-in-one combination vaccine given to Australian toddlers - designed to protect against measles, mumps, rubella and chickenpox - has backed its safety.

Known as the MMRV vaccine, it was one of two new combination vaccines added to the immunisation schedule in 2013, reducing the number of injections babies needed. However there were concerns, raised out of the US, that the MMRV vaccine given to very young children was linked to a greater risk of fever and febrile seizures.

A University of Sydney study, published in journal JAMA Pediatrics, evaluated the way the vaccine is used in Australia. It found no increase in febrile seizures associated with this second dose given at 18 months.

"Children were at no particular risk of having seizures after having the vaccine," Dr Kristine Macartney at the Children's Hospital at Westmead told AAP.

The expert in pediatric infectious diseases says the findings should ease parent concerns that the vaccine does not overwhelm the child's immune system.

5. We've been doing it all wrong: High carb diet worse than high fat, researchers say.

Health experts have controversially called for an overhaul of dietary guidelines after a large international study found a diet high in carbohydrate is associated with greater risk of premature death, not a diet high in fat.

A study of more than 13,500 people from 18 countries, published in the respected medical journal The Lancet, found diets high in carbohydrates were associated with a 28 per cent higher risk of death, compared to low carbohydrate diets.

Diets with a high total fat intake were associated with a 23 per cent lower risk of death, compared to low fat, AAP reports.

The current guidelines recommend that 50-65 per cent of a person's daily calories come from carbohydrates, and less than 10 per cent from saturated fats. The study found the average global diet consisted of at least 60 per cent carbohydrate.

In light of the findings, lead author Dr Mahshid Dehghan at McMaster University, Canada would like the carbohydrate recommendation reduced, saying: "most people's diets in low and middle income countries are very high in carbohydrates, which seem to be linked to worse health outcomes".

The study conclusions have received a mixed reaction from Australian health experts. Dr Alan Barclay, for example, is a consultant dietitian and nutritionist and a Research Associate at the University of Sydney, and says it is an observational study which only shows associations, not proven causes.

6. Sydney Council approves Cloud Arch artwork, dubbed the 'giant tapeworm'.

The controversial $11.3 million public artwork in Sydney's CBD has been likened to a giant tapeworm but passed its final hurdle after City of Sydney councillors approved the project.

Despite its budget blowout of almost $8 million, councillors voted in favour of the Cloud Arch at Tuesday night's meeting, AAP reports.

In a heated debate which spanned more than two hours, Cloud Arch - designed by Japanese artist and architect Junya Ishigami - was called many things from a tapeworm to an icon, but at the centre of the discussion was its cost, which was originally estimated to be $3.5 million in 2014.

Lord Mayor Clover Moore defended the price tag, saying it will be a "magical transformation" that will complement the overall change on George Street. "Cloud Arch going to be most significant artwork created in Australia for decades," she said.

The 58-metre massive steel sculpture is scheduled to soar over George Street near Town Hall by March 2019.