The former children's minister has called on his successor to change an "offensive" and "antiquated" guideline that prohibits prospective adoptive parents from adopting children who are more than 40 years younger than them.

Senator James Reilly called on Minister for Children and Youth Affairs Katherine Zappone to urge the Child and Family Agency – Tusla – to update the guideline on adoption.

Speaking in the Seanad he said: "I am sure there are people of my vintage in this room who probably have siblings whose mother was over 40 when they were born. Many women are leaving childbirth a lot later".

He said the guideline is antiquated and from a different era.

"It is incensing and insulting a lot of people and I am sure they find it insensitive", he added.

The Fine Gael deputy leader said he had spoken to the Master of The National Maternity Hospital at Holles Street, who said they have seen an increase in the number of women over 40 giving birth.

He said most people now "are living a different life and have a much better longevity associated with living in this country and it seems utterly unreasonable to have such a guideline in place." 

"Many people who are parents of children, who are more than 40 years younger than them, find it offensive."

He asked Fine Gael Seanad leader Jerry Buttimer to invite the Minister for Children to discuss this matter and get Tusla to review this guideline.