Economic Survey\u00a02018: Finance Minister Arun Jaitley on Monday tabled the Economic Survey and the national data brought to light some shocking facts. The Economic Survey presented the first-ever estimate of the number of 'unwanted' girls in India. These girls are those whose parents wanted a boy but conceived a girl instead and the number is frightful. As per the survey, 21 million girls are unwanted. The government has arrived at the number by looking at the sex ratio of the last child (SRLC), which is densely male-dominated. This indicated that parents keep trying for a male child until they get what they desire. The survey identified that the huge number of 'unwanted girls' is the result of the 'son meta preference' where a couple does not stop having children after having a daughter. READ| How to download PDF of Economic Survey 2017-18 What is son meta preference? While active sex selection via fetal abortions is widely prevalent, son preference can also manifest itself in a subtler form. Parents may choose to keep having children until they get the desired number of sons. This is called son \u201cmeta\u201d preference. A son \u201cmeta\u201d preference \u2013 even though it does not lead to sex-selective abortion \u2013 may nevertheless be detrimental to female children because it may lead to fewer resources devoted to them (Jayachandran & Pande, 2017). The important thing to note is that this form of sex selection alone will not skew the sex ratio \u2013 either at birth or overall. Therefore, a different measure is required to detect such a \u201cmeta\u201d preference for a son. One indicator that potentially gets at this is the sex ratio of the last child (SRLC). A preference for sons will manifest itself in the SRLC being heavily skewed in favour of boys. On the other hand, an SRLC of close to 1.05:1 would imply that parents\u2019 decisions to continue having children are uncorrelated with previous birth being a son or a daughter. Families continue to have children until they get the desired number of sons. This kind of fertility stopping rule will lead to skewed sex ratios but in different directions: skewed in favor of males if it is the last child, but in favor of females if it is not (see the two panels on India below). Where there is no such fertility stopping rule, the sex ratio will be 1.05 regardless of whether the child is the last one or not.