A heated online debate has been triggered by a mum's response to being told she could not take her son to a wedding.

An engaged couple posted invitations to their ceremony and reception, with a line at the bottom reading "With respect, we would like our special day to be an adults only occasion".

The bride-to-be was shocked when a few weeks later the invitation was returned and had been scribbled on.

'Where is the respect when [name covered] is part of the family,' a guest had written.

'He is my family! That's not respect!'

The woman wrote on the invitation her choice was disrespectful to her son Credit: Facebook

Shocked, the bride posted a photo of the defaced invitation to a wedding shaming Facebook group, where the guest's reaction has been universally slammed.

Is it OK to have a child-free wedding?

Watch the Sunrise Newsfeed discussion above.