Male homosexuality The Y-linked protein NLGN4Y transfer from an older brother to a younger by transfer through the mother's womb, the mother's bloodstream, and her created antibodies reaching her next male fetus' brain, together appear to influence the gayness of the next brother.
Space policy of the United States U.S. President Donald Trump signs the "Space Policy Directive 1" that establishes the foundation for a crewed mission to the Moon, while also maintaining a longer-term NASA goal of landing a man on Mars.
Mount Hope Mount Hope, in a disputed region of Antarctica, is found to be the highest mountain in territory claimed by the United Kingdom. Ben Nevis in Scotland is the highest mountain in the United Kingdom.
France Corsican nationalists demand talks with the French government after a convincing win in the second round of elections for a reformed regional government in Corsica.
Politics of India Rahul Gandhi is elected unopposed as the head of the opposition Congress Party. On 16 January 2018, he is to take over the reins from his mother Sonia Gandhi, who held the position for 19 years.
Ukrainian crisis Ukrainian opposition leader Mikheil Saakashvili is freed from detention following Judge Larysa Tsokol's dismissal of prosecutors’ house arrest request.
Hezbollah political activities Hassan Nasrallah, the Secretary-General of Hezbollah, vows to return to Israel. Tens of thousands of people demonstrate in South Beirut.
Following purges in Turkey Turkey's state news agency announces that prosecutors in Istanbul have requested life sentences against six people, including journalist brothers Ahmet and Mehmet Altan and chronicler Nazli Ilicak. One of the accusations is reportedly "having committed a crime in the name of a terror organization without being a member of it."
Transgender personnel in the United States military U.S. District Judge Colleen Kollar-Kotelly denies a Trump administration request to enforce the ban on transgender troops while this case is under appeal, thereby reaffirming her order that requires the U.S. military to accept transgender recruits effective January 1, 2018.
December 2017 Southern California wildfires The Thomas Fire is the fifth largest in modern Californian history.
Cinema of Saudi Arabia The Ministry of Culture of Saudi Arabia announces that it will lift a ban on commercial cinemas that has lasted more than three decades.
Russian military intervention in the Syrian civil war During a visit to Syria, his first, President Vladimir Putin announces that a significant part of Russian forces will withdraw from Syria now that ISIL has been defeated in the country.
2017 New York City Subway bombing An attempted terrorist attack occurs when a homemade pipe bomb worn by a man explodes near New York City's Port Authority Bus Terminal. Three people, as well as the attacker, are injured. The suspect, identified as Akayed Ullah, is in custody.