The world’s most troublesome borders for illegal migration have one thing in common – more older people on one side than the other. Large gaps in the median age on either side show a difference of 19 years for Northern Africa and Southern Europe, and 11 years for the United States and Central America. “Age differences between sending and receiving nations are a powerful force exerting migratory pressures on borders,” argues Joseph Chamie, a demographer and former director of the UN Population Division. “Any reforms to reduce border crossing must consider the impact of age differences on culture, economies, politics and security.” Population growth is highest in the world’s poorest nations where opportunities are few. Even as analysts insist that immigration contributes to economic growth, right-wing, anti-migrant parties gain political traction with shrill warnings about loss of culture, reduced job opportunities and even security threats. Older voters in wealthy receiving nations fear young newcomers, and global cooperation on social-economic development and reproductive rights is needed to ease extreme imbalances.