The EU has denied claims it plans to question women about their sexual history as part of a drive to improve census statistics, BBC reported.
The European Parliament is due to vote on Wednesday on the harmonisation of census data across the EU.
The European Commission says it needs better quality data on how people live in order to improve policy making.
The Commission has come up with an extensive list of questions it wants all member states to ask in their next census to improve data on housing and population.
In addition to data on nationality, size of family, ethnicity, it also wants to find out about computer literacy, number of cars owned, cooking facilities and "durable consumer goods possessed by the household".
One proposed question asks the "date(s) of the beginning of consensual union(s) of women having ever been in a consensual union: (ii) first consensual union and (ii) current consensual union".
A spokesman for Eurostat, which provides the EU with statistics at European level, said: "This definition has absolutely nothing to do with asking women about their sexual behaviour.
"Consensual union is in fact another term for unmarried partnership.
"Information on consensual unions may be needed in countries where statistics on marriages and on legal marital status do not provide sufficient information on the formation of partnerships.
"Consensual union, as well as information on dates/duration of marriage, is valuable for fertility statistics and extends the knowledge that can be derived from data on number of live-born children."
He said the European Commission proposal contains "no questions related to sexual behaviour" or gardens, as UKIP has claimed.
"The Commission proposal does contain a question related to durable consumer goods, but this refers to major items such as washing machines, fridges and PCs," he added.
The Commission has said it needs more detailed information to plan better policy.
In a document setting out the proposals, it said: "The major objective is to give a sufficiently detailed picture of the structure and characteristics of the population that would allow the in-depth analysis required for planning, administration and monitoring in many policy areas.
"Many such policies have a European component, and the institutions of the European Union as well as member states demand reliable comparisons in the European context."