The double compound eyes of a male St. Mark's fly (Bibio marci), submitted by Dr. David Maitland from Feltwell, UK. (Dr. David Maitland)

A male deer barks at dawn during the annual deer rutting season at Richmond Park in London, Britain, October 9, 2016. (Photo by Toby Melville/Reuters)

Khan, a five-year-old male White Bengal tiger, looks on inside an open-air cage at the Royev Ruchey zoo in Krasnoyarsk, Russia, October 21, 2016. (Photo by Ilya Naymushin/Reuters)

A woman in a wedding gown walks to a mass wedding ceremony, held 17 male inmates, in the Carcel Villa Hermosa prison in Cali, Colombia, August 19, 2016. (Photo by Jaime Saldarriaga/Reuters)

Almost two years old male baby orang-utan Dalai looks on in the zoo in Dresden, Germany, 30 March 2017. Dalai was born to mother Daisy in June 2016. (Photo by Filip Singer/EPA)

The 8th annual Miss International Queen beauty pageant was held in Pattaya in Thailand. The twenty-one contestants from fifteen countries were all born male, so the Miss International Queen 2012 pageant is not an average beauty pageant.

Photo: Panvilas Mongkol, a contestant from Thailand, waits for the start of the final night of Miss International Queen 2012 transgender/transsexual beauty pageant in Pattaya November 2, 2012. Some 21 contestants from 15 countries, all of them born male, compete in the week-long event for the crown of Miss International Queen 2012. (Photo by Damir Sagolj/Reuters)

A woman stands in a gift shop in central Rason city, part of the special economic zone northeast of Pyongyang, in this August 30, 2011 file photo. North Korea is a militarized, male-dominated society, but it is women who are making the money as the insular nation allows an unofficial market-based economy to take shape. (Photo by Carlos Barria/Reuters)

An officer of the Afghan border police throws an assault rifle to a policeman participating in a military exercise on the outskirts of Herat, Afghanistan, Monday, September 7, 2015. Twelve female and seventy male border police personnel participated in the military exercise near the border with Iran in Herat province. (Photo by Hoshang Hashimi/AP Photo)