A Fianna Fáil TD claims an increasing number of foetuses are being aborted because of clefts.
Sean Haughey spoke against repealing the Eighth Amendment and said he was concerned about the power that would be given to the Dáil, if they were allowed to legislate for abortion.
Mr Haughey said it will lead to healthy babies being aborted.
He said: "It has become clear that a growing number of terminations are being carried out due to cleft, so in short lives are being ended on the basis of appearance and babies must be physically perfect.
"This surely should not be the case in a humane and tolerant society.
"We should also examine the situation with regards to Down Syndrome. In the UK 90% of babies that are diagnosed with Down Syndrome in the womb are aborted."
A cleft palate is when the roof of the mouth has an opening into the nose and it can lead feeding problems, speech problems, hearing problems, and frequent ear infections.
However, Disabilities Minister Finian McGrath appealed for TDs not to drag people with Down Syndrome into the debate.
He said: "Our children, and I speak as a parent of a daughter with Down Syndrome, our children and our adults listen to the radio, watch the TV and read the media articles - and the tone of this debate is crucual.
"Respect has got to be at the top of the agenda."
It comes as Fianna Fáil leader Micheál Martin faced criticism from a number of his own TDs over his speech in favour of repealing the Eighth Amendment last week.
At a private meeting of the parliamentary party at Leinster House, TDs made it clear to Mr Martin that a majority of them do not support his view.
Sources at the meeting, which lasted for more than two hours, said that while the mood was calm and respectful, Mr Martin was left in no doubt as to where the majority of the party stand.
The primary criticism, according to sources, was of a failure to warn members that he would express support for repealing the Eighth Amendment and for permitting legal abortions up to 12 weeks.
There was criticism of what some people called the “heavy-handed” approach taken by some frontbench members who sought to dissuade TDs and senators from attending a meeting on Tuesday night organised by Carlow-Kilkenny TD Bobby Aylward.
In total, more than 30 TDs and senators contributed to the meeting, with 70% speaking in favour of retaining the 1983 constitutional amendment which recognises the equal right to life of a mother and her unborn.
Several TDs said they were “very disappointed” with Mr Martin’s Dáil address but said that they ultimately respected it was his personal view.
Responding to the criticism, Mr Martin said it was never his intention to keep the parliamentary party in the dark.
He argued that a 20-minute speaking slot came available in the Dáil chamber and it would allow him set out his argument and the context of his argument without interruption.
“Micheál finished very strongly and said that the Dáil debate was the best place for him to outline his position and not get distracted. While there was some griping from the room, he dealt with it,” said one TD.
Mr Martin made it clear he had no intention of stopping anyone from speaking their mind and reminded everyone that a free vote will apply.
“He said he has no problem with people going on TV and radio and expressing their view, and, by and large, most people accepted that,” said a source.