CAIRO — Somewhere in Egypt, around lunchtime Tuesday, the country reached a major milestone: its 100 millionth citizen was born.

The birth of that citizen — whom officials identified as a girl named Yasmine Rabi’e, in a village in Minya governorate — was noted in Cairo by a giant counter outside the country’s national statistics agency that has been ticking upward for years.

Hitting 100,000,000 marked human plenty, certainly, but also an uneasy moment in a country gripped by worries about the effects of the demographic explosion on deepening poverty, rising unemployment and a growing scarcity of basic resources like land and water.

Egypt’s cabinet said last week that it was on “high alert” to fight population growth, which President Abdel Fattah el-Sisi has described as a threat to national security on par with terrorism. If unchecked, the population could reach 128 million by 2030, officials say.