The debate kicked off when fellow CVP politician Michael Kaufmann tweeted a message from former Swiss president Ruth Metzler-Arnold calling for the Swiss parliament to ensure same-sex couples had full equality with married couples.
Although Switzerland introduced civil partnership for same-sex couples in 2005, these couples do not enjoy full equality with married couples on issues including tax, social security, adoption and fertility treatment.
A Swiss parliamentary commission is set to meet on May 17th to discuss the legal ramifications of allowing gay marriage. The issue will then go before the full parliament for discussion in the summer 2019 session.
But Kaufmann’s tweet of support for equal marriage rights did not sit well with the president of the CVP in the canton on Lucerne Christian Ineichen. He replied that “we should stay within the limits of biology”.
Asked by Kaufmann to clarify what he meant by the “limits of biology”, Ineichen said: “Man +woman: OK. Woman+Woman: sort of OK. Man+Man: not OK.”
The comment sparked angry reactions, with Marco Baumann of the Free Democratic Party (FDP) in Lucerne and a board member for gay rights group Pink Cross Switzerland, saying the Lucerne wing of the CVP was displaying its “backward-looking, deeply conservative face”.
Meanwhile, Michael Kaufmann described the comments as “un-Christian”.
Ineichen was quick to clarify that he was referring to the adoption rights and not gay marriage as such.
"Woman can organise a pregnancy. But two men simply cannot make a child together," he told Swiss news site Watson.
“I believe family policy should be guided by the rules imposed by biology,” he told regional daily Luzerner Zeitung.
He said he accepted “new ways of living and partnership models” but “found it difficult when that suddenly means turning the whole idea of families on its head”.
“It’s noteworthy that those very people who always demand tolerance are very intolerant towards people like me who have different opinions,” he said.
But he conceded his party didn’t share his opinion and said he would support the CVP.
The right to marriage and a family are enshrined under Article 14 of the Swiss constitution.
On May 17th, the legal affairs committee of the Swiss lower house will discuss whether legal changes or a constitutional amendment are necessary to allow for gay marriage.
If the commission and the parliament decide the constitution must be changed, this would need to be ratified in a popular referendum.
So-called equal marriage in Switzerland would also have an impact on the naturalisation of foreign residents.
Currently, foreign spouses of Swiss citizens are eligible for facilitated naturalisation, an easier process than the longer ‘standard' naturalisation process. If equal marriage were law, same-sex spouses and heterosexual civil partners could then be eligible for the facilitated system.
As of January 2018, same-sex couples can adopt adopt their partner's children from a previous relationship.
At the time that law was discussed in parliament some MPs opposing the move said they feared it was a ‘salami' tactic that could lead to legalising adoption for single gay people and surrogacy. However a campaign to launch a referendum against the law change failed to get the required number of signatures.