August 3 is National Twins Day! Learn all about Irish twins here.

Strictly speaking, 'Irish twins' are only those siblings born within 12 months (or less) of each other.

Read More: Twins honored for saving their granny's life in a babysitting emergency

The phrase originates from the United States and Britain of the 19th century and was a disparaging term used to describe siblings from large, and mostly poor, Irish immigrant families.

Back then it was common for families to have children in quick succession as most families adhered strictly to the Church’s teaching on contraception.

When someone mentioned ‘Irish twins’ it usually implied that the family was Catholic and also hinted that the user thought their typically large families were impractical and that they should start using contraception. 

Read More: WATCH: Tom Hanks creates 'Toy Story' video for formerly conjoined twins in Co Cork

Do people still find the term offensive? The internet suggests so.

@SavannahGuthrie nasty and unnecessary comment about J.S's babies being "Irish twins" this a.m. Originally meant and remains offensive.

— JoAnn Taylor (@mollypitcher2) December 26, 2012

How @FoodNetwork can let the loaded, offensive phrase "Irish Twins" on television is beyond me. #boycott #FoodNetworkStar

— LawSchool$uccess (@SpecterProf) July 18, 2016

@InfieldSingle Heh. Around here, siblings born within a year of each other are sometimes called Irish twins. Offensive, but colorful.

— Colleen Barry (@CopyCurmudgeon) August 17, 2011

Although not everyone is so sure.

Even that whole "Irish twins" thing isn't offensive anymore, now people say it like it's cute.

— Billie Jean Davy (@ScreamQueenMom) March 11, 2014

As Irish Catholics have increasingly begun to disregard Church teaching regarding family planning and families sizes have plummeted as a result the use of the phrase has declined, although as the tweets above show it still provokes a strong reaction among sections of the diaspora.

Read More: One wild Irish love story with the world’s most famous conjoined twins

* Originally published in June 2017.

What do you think about the term 'Irish twins'? Tell us in the comments below!