NEW DELHI — A deeply felt preference for boys has left more than 63 million women statistically “missing” across India, and more than 21 million girls unwanted by their families, government officials say.

The skewed ratio of men to women is largely the result of sex-selective abortions, and better nutrition and medical care for boys, according to the government’s annual economic survey, which was released Monday. In addition, the survey found that “families where a son is born are more likely to stop having children than families where a girl is born.”

Statistics indicate that India has 63 million fewer women than it should have, scientists say, a “missing” population explained by sex-selective abortions and a range of other issues.

The birth of a son is often a cause for celebration and family pride, while the birth of a daughter can be a time of embarrassment and even mourning as parents look toward the immense debts they’ll need to take on to pay for marriage dowries. Studies have long shown that Indian girls are less educated than boys, have poorer nutrition and get less medical attention. Many women — including educated, wealthy women — say they face intense pressure, most often from mothers-in-law, to have sons.

By analyzing birth rates and the gender of last-born children, the report also estimated that more than 21 million Indian girls are not wanted by their families.

“The challenge of gender is long-standing, probably going back millennia,” wrote the report’s author, chief economic adviser Arvind Subramanian, noting that India must “confront the societal preference for boys.”

The report also noted that increasing wealth does not mean an end to male preferences among families, with some comparatively wealthy areas, including New Delhi, faring worse over the years.

Many of the best scores for women’s development, the report noted, were in India’s northeast — “a model for the rest of the country” — a cluster of states that hang off the country’s edge where most people are ethnically closer to China and Myanmar, and where some people don’t even see themselves as Indian.