Niamey - Niger's president has sounded the alarm over his country's world-leading birth rate, labelling the average of over seven children per household a "handicap" to development in the impoverished west African nation. Mahamadou Issoufou said that at the current rate, Niger's population would more than double by 2035 and hit 75 million by the middle of the century. "Common sense compels us to reflect now on this future," he said on Wednesday during a televised address on the 57th anniversary of Niger's independence from France. "If we cannot educate, train and care for our youth and offer them employment opportunities... they will become a handicap, or even a menace to social cohesion and prosperity." Deeply poor Niger has the world's highest birth rate of 7.6 children per household, and its population of 18 million is growing at close to four percent a year. The United Nations estimates that the population of west Africa could reach a billion people by 2050 and senior politicians in the region last month called for measures to half birth rates. Niger has a number of factors contributing to its ballooning population, not least the fact that three quarters of women are married before they reach 18 and that contraceptive use is just 12% nationwide. "We need to act now," Issoufou said during his address, adding that the government wanted to put a stop to underage marriage and increase education rates among girls.