Senator Ronan Mullen has said if gay conversion therapies can do no harm, they should be legal.
Speaking during Seanad business on Thursday, the NUI-elected senator responded to the issue which was raised by Senator Fintan Warfield.
Seantor Mullen said: "What I would say is this: in relation to issues like this, the highest value is what people want provided it doesn't do harm.
"And I don't know enough about it at this stage - but if it can be shown that this is harmful to people, then there is a very good case to make it unlawful.
"If it cannot be shown to be harmful to people, then you're back into the realm of individual choice.
"And I say this because I don't think we talk enough in these Houses about the importance of an evidence base for what is proposed.
The Independent senator added: "I would hope that whether it's in this area, or indeed the very fraught and difficult area of transgender persons and their rights and needs, that we would look honestly at what the current evidence base is."
He went on to claim: "A lot of parents I know are quite concerned at what's being taught in schools now in the name of equality in relation to the transgender issues, and they question whether children's best interests are being served by what is now often proposed".
Senator Mullen was a strong advocate for a 'No' vote in the marriage equality referendum in 2015.
He also advocated for a 'No' vote in the referendum to repeal the Eighth Amendment last year.
Sinn Féin Senator Warfield has previously launched legislation to prohibit conversion therapy in Ireland.
He said the legisaltion "aims to prohibit conversion therapy, as a deceptive and harmful act or practice against a person’s sexual orientation, gender identity and, or gender expression."
Depending on techniques used, conversion therapy has been found by the United Nations to be unethical, unscientific, ineffective and, in some instances, tantamount to torture.
A report by the UN Human Rights Office from 2015 recommended an end to abusive therapies and treatments - including so-called 'conversion' therapy, forced sterilisation of transgender persons and certain medical procedures on intersex children.
