Slovaks voted Saturday in a referendum intended to strengthen a constitutional ban on same-sex marriage and adoption, highlighting conservative values in this ex-communist EU state.
Opinion polls however suggested voter turnout will fall well short of the 50 percent threshold required for the referendum to be valid.
A 2014 constitutional amendment which defines marriage as a union of man and wife -- effectively banning same-sex unions -- will therefore remain intact.
In this predominantly Roman Catholic easternmost member of the European Union, many see equality and diversity as liberal values "imported" from the West to undermine the traditional family.  
The campaign ahead of the ballot was marred by hate speech.
Slovakia's ban contrasts sharply with the legalisation of same-sex marriage in more than a dozen countries, including Argentina, France and the United States but echoes similar bans in fellow ex-communist eastern EU members Croatia, Hungary and Poland.
While EU rules prevent outright discrimination against lesbians and gays on the basis of sexual preference, same-sex couples still cannot share healthcare and tax and inheritance benefits.
While conservatives pitched their campaign "say 'yes' for the family", gay rights advocates encouraged people to vote with their legs by boycotting it.
"The referendum will show whether Slovakia will join the growing wave of European measures promoting equality in human rights or swim against the current," Jana Malovicova, head of Amnesty International Slovakia said in a Saturday statement.
Earlier this week Amnesty accused the conservative circles that launched the referendum of "pandering to homophobic discrimination".
Last month, Slovak SRo public radio pulled an episode of a regular religious programme that included hate speech against sexual minorities.
A transcript of the unaired sermon by a Greek Catholic priest slanders gays as "filth" and a "plague" that must be driven out of Slovakia.
- 'Where's the mother?' -
The vote is also focused on adoption rights for same-sex couples and whether sex education and lessons on euthanasia should be made compulsory at school.
One of several controversial videos posted on YouTube by gay marriage opponents shows an orphan asking "Where's the mother?" when he discovers that his adoptive parents are both male.
Robert Godal showed up with his wife and two kids to vote at a Bratislava polling station Saturday so that "only the traditional family should have the right to adopt and raise children," he told AFP.   
"The European Parliament and some EU members have passed laws that undermine the unique nature of marriage, families and children's rights," Anton Chromik, spokesman for the Alliance for Family (AZR) that is spearheading the referendum, told AFP.
However, the 28-state bloc leaves decision-making on marriage and family policy up to each member.
A 2012 opinion poll in Slovakia showed that 47 percent of respondents supported civil unions for gays. Thirty-eight percent were opposed in the country of 5.4 million people, where 69 percent identified themselves as Roman Catholic in a 2011 census.
The Catholic church in Slovakia staunchly backed the constitutional ban on gay marriage introduced last year, but the issue is not one at the forefront of public debate.
"Gay marriage and adoption don't matter enough to people to show up at the ballot box," Martin Slosiarik, an analyst with the Bratislava-based Focus pollsters told AFP.
"Of the voters who turn up, those supporting the gay marriage ban will be in the majority but it won't be enough for the referendum to be valid and legally binding," he explained.
Bratislava art gallery owner Andrea Pallang, 40, who has been living with her girlfriend for eight years, boycotted the ballot.
"I voted with my legs, I don't think that the majority should decide on the life of a minority in a popular vote."
"I pay taxes and work just like everyone else so I should have the same rights as everyone else," Andrea's girlfriend Ivona, 26, told AFP.
Results are expected late Saturday.