Lion cubs, who were born after a pioneering veterinary procedure that involved a reversed vasectomy of their father, are presented to the media, at Buin Zoo, in the outskirts of Santiago, Chile May 4, 2017. REUTERS/Ivan Alvarado

A lion cub (L), who was born after a pioneering veterinary procedure that involved a reversed vasectomy of its father, is presented to the media, at Buin Zoo, in the outskirts of Santiago, Chile May 4, 2017. REUTERS/Ivan Alvarado

Lion cubs, who were born after a pioneering veterinary procedure that involved a reversed vasectomy of their father, are presented to the media, at Buin Zoo, in the outskirts of Santiago, Chile May 4, 2017. REUTERS/Ivan Alvarado

Lion cubs, who were born after a pioneering veterinary procedure that involved a reversed vasectomy of their father, are presented to the media, at Buin Zoo, in the outskirts of Santiago, Chile May 4, 2017. REUTERS/Ivan Alvarado

Lion cubs, who were born after a pioneering veterinary procedure that involved a reversed vasectomy of their father, are presented to the media, at Buin Zoo, in the outskirts of Santiago, Chile May 4, 2017. REUTERS/Ivan Alvarado

Lion cubs, who were born after a pioneering veterinary procedure that involved a reversed vasectomy of their father, are presented to the media, at Buin Zoo, in the outskirts of Santiago, Chile May 4, 2017. REUTERS/Ivan Alvarado

A lion cub (R), who was born after a pioneering veterinary procedure that involved a reversed vasectomy of its father, is presented to the media at Buin Zoo, in the outskirts of Santiago, Chile May 4, 2017. REUTERS/Ivan Alvarado

Women wait for sterilization surgery at a hospital in Caracas, Venezuela July 27, 2016. REUTERS/Carlos Garcia Rawlins SEARCH "STERILIZATION CHILD" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES.

Women wait for sterilization surgery a hospital in Caracas, Venezuela July 27, 2016. REUTERS/Carlos Garcia Rawlins SEARCH "STERILIZATION CHILD" FOR THIS STORY. SEARCH "THE WIDER IMAGE" FOR ALL STORIES. TPX IMAGES OF THE DAY

White lion cubs are seen at the Drakenstein Lion Park near Cape Town December 29, 2015. A South African lion called Brutus who fathered three "miracle" cubs despite having had a vasectomy in his youth is going back to the vet to have the operation a second time. Brutus and his partner Nala, who live at the Drakenstein Lion Park near Cape Town, stunned staff at the sanctuary when she gave birth to the cubs just before Christmas. REUTERS/Mark Wessels

A white lion named Nala is seen at the Drakenstein Lion Park near Cape Town December 29, 2015. Brutus, who fathered three "miracle" cubs despite having had a vasectomy in his youth, is going back to the vet to have the operation a second time. Brutus and his partner Nala, who live at the Drakenstein Lion Park, stunned staff at the sanctuary when she gave birth to the cubs just before Christmas. REUTERS/Mark Wessels

A white lion named Nala (L) and her partner Brutus are seen at the Drakenstein Lion Park near Cape Town December 29, 2015. Brutus, who fathered three "miracle" cubs despite having had a vasectomy in his youth, is going back to the vet to have the operation a second time. Brutus and Nala, who live at the Drakenstein Lion Park, stunned staff at the sanctuary when she gave birth to the cubs just before Christmas. REUTERS/Mark Wessels

A white lion named Brutus is seen at the Drakenstein Lion Park near Cape Town December 29, 2015. Brutus, who fathered three "miracle" cubs despite having had a vasectomy in his youth, is going back to the vet to have the operation a second time. Brutus and his partner Nala, who live at the Drakenstein Lion Park, stunned staff at the sanctuary when she gave birth to the cubs just before Christmas. REUTERS/Mark Wessels TPX IMAGES OF THE DAY

Women, who underwent sterilization surgery at a government mass sterilisation camp, pose for pictures inside a hospital at Bilaspur district in the eastern Indian state of Chhattisgarh November 14, 2014. The doctor whose sterilisation of 83 women in less than three hours ended in at least a dozen deaths said on Thursday the express operations were his moral responsibility and blamed adulterated medicines for the tragedy. REUTERS/Anindito Mukherjee (INDIA - Tags: HEALTH CRIME LAW SOCIETY)

A doctor talks to a man availing a free Vasectomy operation during a Family Planning fair conducted by the United Nations Population Fund (UNFPA) in Tondo, Manila July 11, 2012. REUTERS/Erik De Castro (PHILIPPINES - Tags: POLITICS HEALTH SOCIETY POVERTY)

A doctor screens a resident (L) who wants undergo vasectomy, a family planning procedure, in Manila's poor residential district of Baseco July 11, 2012. The Family Planning Fair, which is a part of the United Nations' celebration of World Population day in Manila, offered more than 1000 community members free contraceptives, tubal ligation, vasectomy and implants, a statement from "Likhaan", a non-governmental organization said. REUTERS/Erik De Castro (PHILIPPINES - Tags: HEALTH SOCIETY)

Filipino housewives listen during a family planning session in Manila's poor residential district of Baseco July 11, 2012. The Family Planning Fair, which is a part of the United Nations' celebration of World Population day in Manila, offered more than 1000 community members free contraceptives, tubal ligation, vasectomy and implants, a statement from "Likhaan", a non-governmental organization said. REUTERS/Erik De Castro (PHILIPPINES - Tags: HEALTH SOCIETY)

A doctor inserts a contraceptive implant into an housewife's arm as part of Family Planning services in Manila's poor residential district of Baseco July 11, 2012. The Family Planning Fair, which is a part of the United Nations' celebration of World Population day in Manila, offered more than 1,000 community members free contraceptives, tubal ligation, vasectomy and implants, a statement from "Likhaan", a non-governmental organization said. REUTERS/Erik De Castro (PHILIPPINES - Tags: HEALTH SOCIETY)

Filipino housewives take part in a Family Planning session in Manila's poor residential district of Baseco July 11, 2012. The Family Planning Fair, which is a part of the United Nations' celebration of World Population day in Manila, offered more than 1000 community members free contraceptives, tubal ligation, vasectomy and implants, a statement from "Likhaan", a non-governmental organization said. REUTERS/Erik De Castro (PHILIPPINES - Tags: HEALTH SOCIETY)

A doctor inserts a contraceptive implant into an housewife's arm as part of Family Planning services in Manila's poor residential district of Baseco July 11, 2012. The Family Planning Fair, which is a part of the United Nations' celebration of World Population day in Manila, offered more than 1000 community members free contraceptives, tubal ligation, vasectomy and implants, a statement from "Likhaan", a non-governmental organization said. REUTERS/Erik De Castro (PHILIPPINES - Tags: HEALTH SOCIETY)

Filipino housewives listen during a family planning session in Manila's poor residential district of Baseco July 11, 2012. The Family Planning Fair, which is a part of the United Nations' celebration of World Population day in Manila, offered more than 1000 community members free contraceptives, tubal ligation, vasectomy and implants, a statement from "Likhaan", a non-governmental organization said. REUTERS/Erik De Castro (PHILIPPINES - Tags: HEALTH SOCIETY)

Doctors stand around Mansur as he undergoes vasectomy surgery at a family planning clinic in Jakarta October 27, 2011. Mansur, killing his dream to have a daughter, went to a clinic and had vasectomy, sterilisation for men: a method that has not go down well in Indonesia to put brakes on population growth. The United Nations predicted that on October 31, the world population will hit seven billion people. Picture taken October 27, 2011. REUTERS/Beawiharta (INDONESIA - Tags: SOCIETY HEALTH)

Doctors stand around Mansur as he undergoes vasectomy surgery at a family planning clinic in Jakarta October 27, 2011. Mansur, killing his dream to have a daughter, went to a clinic and had vasectomy, sterilisation for men: a method that has not go down well in Indonesia to put brakes on population growth. The United Nations predicted that on October 31, the world population will hit seven billion people. Picture taken October 27, 2011. REUTERS/Beawiharta (INDONESIA - Tags: SOCIETY HEALTH)

Thai veterinarian Juthamas Sumanam performs a vasectomy on a macaque monkey in the town of Lopburi, 155 km (96 miles) north of Bangkok, August 19, 2009. Thailand started a birth control programme to sterilise male monkeys with the aim of controlling their population in the famous monkey town of Lopburi. The programme took place after many villagers complained about the increasing numbers of monkeys and their aggressive attacks on people. Picture taken August 19, 2009. REUTERS/Chaiwat Subprasom (THAILAND SOCIETY ANIMALS HEALTH)

A Thai veterinarian prepares male macaque monkeys before their vasectomy procedures in the town of Lopburi, 155 km (96 miles) north of Bangkok, August 19, 2009. Thailand started a birth control programme to sterilise male monkeys with the aim of controlling their population in the famous monkey town of Lopburi. The programme took place after many villagers complained about the increasing numbers of monkeys and their aggressive attacks on people. Picture taken August 19, 2009. REUTERS/Chaiwat Subprasom (THAILAND SOCIETY ANIMALS HEALTH)

A Thai veterinarian prepares an anaesthesia shot to be injected into a macaque monkey for its vasectomy procedure in the town of Lopburi, 155 km (96 miles) north of Bangkok August 19, 2009. Thailand started a birth control programme to sterilise male monkeys with the aim of controlling their population in the famous monkey town of Lopburi. The programme took place after many villagers complained about the increasing numbers of monkeys and their aggressive attacks on people. Picture taken August 19, 2009. REUTERS/Chaiwat Subprasom (THAILAND ANIMALS HEALTH)

A Thai veterinarian reaches to inject a macaque monkey with anaesthesia to prepare it for a vasectomy in the town of Lopburi, 155 km (96 miles) north of Bangkok August 19, 2009. Thailand started a birth control programme to sterilise male monkeys with the aim of controlling their population in the famous monkey town of Lopburi. The programme took place after many villagers complained about the increasing numbers of monkeys and their aggressive attacks on people. Picture taken August 19, 2009. REUTERS/Chaiwat Subprasom (THAILAND ANIMALS HEALTH)

A Thai veterinarian prepares macaque monkeys before their vasectomy procedures in the town of Lopburi, 155 km (96 miles) north of Bangkok, August 19, 2009. Thailand started a birth control programme to sterilise male monkeys with the aim of controlling their population in the famous monkey town of Lopburi. The programme took place after many villagers complained about the increasing numbers of monkeys and their aggressive attacks on people. Picture taken August 19, 2009. REUTERS/Chaiwat Subprasom (THAILAND SOCIETY ANIMALS HEALTH)

A Thai veterinarian prepares macaque monkeys before their vasectomy procedures in the town of Lopburi, 155 km (96 miles) north of Bangkok, August 19, 2009. Thailand started a birth control programme to sterilise male monkeys with the aim of controlling their population in the famous monkey town of Lopburi. The programme took place after many villagers complained about the increasing numbers of monkeys and their aggressive attacks on people. Picture taken August 19, 2009. REUTERS/Chaiwat Subprasom (THAILAND SOCIETY ANIMALS HEALTH)

Thai veterinarian Juthamas Sumanam (L) performs a vasectomy on a macaque monkey in the town of Lopburi, 155 km (96 miles) north of Bangkok, August 19, 2009. Thailand started a birth control programme to sterilise male monkeys with the aim of controlling their population in the famous monkey town of Lopburi. The programme took place after many villagers complained about the increasing numbers of monkeys and their aggressive attacks on people. Picture taken August 19, 2009. REUTERS/Chaiwat Subprasom (THAILAND SOCIETY ANIMALS HEALTH)

A Thai veterinarian prepares male macaque monkeys before their vasectomy procedures in the town of Lopburi, 155 km (96 miles) north of Bangkok, August 19, 2009. Thailand started a birth control programme to sterilise male monkeys with the aim of controlling their population in the famous monkey town of Lopburi. The programme took place after many villagers complained about the increasing numbers of monkeys and their aggressive attacks on people. Picture taken August 19, 2009. REUTERS/Chaiwat Subprasom (THAILAND SOCIETY ANIMALS HEALTH)

Thai veterinarian Juthamas Sumanam performs a vasectomy on a macaque monkey in the town of Lopburi, 155 km (96 miles) north of Bangkok, August 19, 2009. Thailand started a birth control programme to sterilise male monkeys with the aim of controlling their population in the famous monkey town of Lopburi. The programme took place after many villagers complained about the increasing numbers of monkeys and their aggressive attacks on people. Picture taken August 19, 2009. REUTERS/Chaiwat Subprasom (THAILAND SOCIETY ANIMALS HEALTH)

Thai veterinarian Juthamas Sumanam performs a vasectomy on a macaque monkey in the town of Lopburi, 155 km (96 miles) north of Bangkok, August 19, 2009. Thailand started a birth control programme to sterilise male monkeys with the aim of controlling their population in the famous monkey town of Lopburi. The programme took place after many villagers complained about the increasing numbers of monkeys and their aggressive attacks on people. Picture taken August 19, 2009. REUTERS/Chaiwat Subprasom (THAILAND ANIMALS SOCIETY)

A veterinarian operates on a dog during a sterilization exercise in a veterinary camp in Srinagar May 10, 2008. Authorities had decided to round up hundreds of stray dogs for sterilization after receiving complaints that packs of dogs were biting people and chasing vehicles, officials said. REUTERS/Danish Ismail (INDIAN-ADMINISTERED KASHMIR)

A Thai veterinarian performs a vasectomy on a male monkey at the temple in the western Thai province of Petburi July 16. The monkey population at Khao Wang hill has grown to about 3,000, and the the provincial administration has launched a campaign to control the population as the monkeys are annoying the town folk and tourists.

A Thai veterinarian performs a vasectomy on a male monkey at the temple in the western Thai province of Petburi July 16. The monkey population at Khao Wang hill has grown to about 3,000, and the the provincial administration has launched a campaign to control the population as the monkeys are annoying the town folk and tourists.

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