The dispute is the latest in several spats highlighting rising tensions between Turkey and EU states in the wake of the botched July 15 coup followed by a relentless crackdown that angered Europe.
Swedish Foreign Minister Margot Wallstrom had tweeted on her official account that the "Turkish decision to allow sex with children under 15 must be reversed", following a controversial ruling by the Turkish constitutional court.
"It is a scandal for a foreign minister to post such a tweet based on false news or speculation," Turkish Foreign Minister Mevlut Cavusoglu said in televised comments, adding that the Swedish ambassador to Ankara had been summoned to his ministry.
Cavusoglu blasted the "unacceptable" tweet, saying Wallstrom should have acted "responsibly".
"A foreign minister should not tell lies and should not adopt an approach accusing Turkey," Cavusoglu said. "Yes to criticism but this is a slander, a lie."
Turkey's constitutional court in July annulled a criminal code provision punishing as "sexual abuse" all sexual acts involving children under the age of 15, responding to a petition brought by a lower court.
The top court has given a six-month period for parliament to draw up a new law based on its ruling.
The lower court that brought the petition was worried there was no distinction between cases of sexual acts involving a young teenager or a toddler.
The legal age of consent in Turkey remains 18 and was not affected by the ruling. But it drew a furious response from activists worried it would open the way for unpunished child sexual abuse.
Cavusoglu said the Turkish government was determined to fight child abuse and added the justice ministry was currently working on new rules.
In a war of words with Stockholm on Twitter, Turkey's Deputy Prime Minister Mehmet Simsek told Wallstrom: "You are clearly misinformed. There is no such stupid thing in Turkey. Please get your facts right."
'Capital of racism'
Ankara also summoned the Austrian charge d'affaires at the weekend in protest over a news ticker at Vienna airport about the age of consent controversy.
The news ticker -- above an arrivals board and supplied by mass-circulation daily Kronen-Zeitung -- said in German "Turkey allows sex with children under 15".
The foreign ministry expressed outrage that the airport was being abused by a "discredited newspaper to spread its irresponsible, distorted and falsified messages in order to defame a friendly country".
Cavusoglu hit back at what he said was growing racism and Islamophobia engulfing the European continent.
"It is alarming that the slander campaign that started in Austria -- the capital of racism and Islamophobia -- is spreading into Sweden which is actually more sensitive on human rights," he said.
The Turkish ambassador to Stockholm was due to meet the Swedish foreign minister on Monday, Cavusoglu said, adding that he would also speak with Wallstrom on the phone.
Ties between Turkey and Austria have strained after a number of Austrian politicians spoke out against Turkey's longstanding bid to join the EU, particularly after the vast purge that followed the coup bid.
Austrian Defence Minister Hans-Peter Doskozil has compared Turkey to a "dictatorship".