In vitro fertilization (IVF) has allowed women to delay birth and pursue a career, but it massively increasesthe risk of twin birth. We investigate the extent to which having twins hampers women's careers after birth. To do this, we leverage a single embryo transfer (SET) mandate for IVF...

IVF allows women to delay birth and pursue careers, but IVF massively increases the risk of twin birth. There is limited evidence of how having twins influences women's post-birth careers. We investigate this, leveraging a single embryo transfer (SET) mandate implemented in Sweden in 2003,...

IVF allows women to delay birth and pursue careers, but IVF massively increases the risk of twin birth. There is limited evidence of how having twins influences women's post-birth careers. We investigate this, leveraging a single embryo transfer (SET) mandate implemented in Sweden in 2003,...

In vitro fertilization (IVF) has allowed women to delay birth and pursue a career, but it massively increasesthe risk of twin birth. We investigate the extent to which having twins hampers women's careers after birth. To do this, we leverage a single embryo transfer (SET) mandate for IVF...

Twin births are often construed as a natural experiment in the social and natural sciences on the premise that the occurrence of twins is quasi-random. We present new population-level evidence that challenges this premise. Using individual data for more than 18 million births (more than 500,000...

Twin births are often construed as a natural experiment in the social and natural sciences on the premise that the occurrence of twins is quasi-random. We present new population-level evidence that challenges this premise. Using individual data for 17 million births in 72 countries, we...

Twin births are often used to instrument fertility to address (negative) selection of women into fertility. However recent work shows positive selection of women into twin birth. Thus, while OLS estimates will tend to be downward biased, twin-IV estimates will tend to be upward biased. This is...

The occurrence of twin births has been widely used as a natural experiment. With a focus upon the use of twin births for identification of causal effects in economics, this chapter provides a critical review of methods and results.