DHAKA: Bangladesh will overhaul its school curriculum and introduce a new subject covering reproductive health as the country addresses its biggest surge in child marriage in more than two decades, top education officials have said.  Although the legal age for marriage in Bangladesh is 18 for women and 21 for men, the nation has the highest rate of child marriage in South Asia. Of its 167 million residents, some 38 million women were married before their 18th birthday — 13 million of them before they were 15 — according to BRAC, the largest development organization in the country.…