JOURNAL OF ETHNIC AND MIGRATION STUDIES 973 important discussion arena for citizenship, statelessness, and migration. Gonzales (2016), who wrote about the experiences of Mexican-American children caught in an uncertain legal status, highlighted how some Mexican-American children are temporarily protected and build a feeling of belonging to the host society during their childhood (Gonzales 2016, 7–9). Such children then experience a ‘transition to illegality’ by experiencing exclusion from possibilities they believed were theirs as they transition to adulthood (Gonzales 2016, 12–13). This article integrates the two aforementioned theoretical frameworks, arguing how abandoned children’s transition to statelessness occurs as time passes during their childhood, following two main routes – presumptive foreign nationality and considered nationality. The analyses herein are based on studies of children from mixed-status families (Castañeda 2019), forcibly deported youth (Coutin 2007; Dreby 2015), left-behind children from migrant homes without their parent(s) (Parreñas 2005), multigenerational transnational migrant families (Allerton 2018; Ball, Butt, and Beazley 2017), children born to noncitizen migrant mothers (Constable 2014; Suzuki 2015), and abandoned children (Mahdavi 2016). The legal production of illegality The ‘legal production of illegality’ (Mahdavi 2016, 122) is an analytical framework considering how illegality is created by laws that define people as citizens or noncitizens (Boehm 2012, 136; Coutin 2007, 26; De Genova 2004, 161). The approach was first put forward by scholars such as De Genova (2004), who argued on the historical specificity of contemporary Mexican migration to the US. He argued that it is the disciplinary operation of an apparatus for the everyday production of migrant ‘illegality’, deportability, and not deportation per se, that has historically rendered Mexican labour as a distinctly deportable commodity (De Genova 2004, 179). Mahdavi (2016) proposed the framework based on the work of Boehm (2012) and Coutin (2007), who explored Mexican mixed-status families and young people in such families in the U.S. Mahdavi applied this notion to children born to unmarried noncitizen mothers in Kuwait (Mahdavi 2016, 124). Boehm studied undocumented migrant children who, in particular circumstances, are de facto members of a nation with complex ties with U.S. communities (living in neighbourhoods, attending school, working, shopping, eating out, going to parks and public spaces, and interacting with community members daily) who are not state-recognised citizens (facing threats of deportation, an inability to move freely, and lack of access to health care) (Boehm 2012, 136; Coutin 2007, 27). Investigating the cases of youth who emigrated from Mexico to the U.S. as infants, Boehm and Coutin illustrated the legal production of (il)legality (Boehm 2012, 136; Coutin 2007, 26), arguing that for young people who engage in identical daily activities as their American counterparts, the U.S. state constructs their illegality, defining individual migrants as ‘aliens’ who are ‘legal’ or ‘illegal’. In cases within Japan, these arguments on the citizenship, legality, and illegality of children born to migrant mothers in Japan have also been also discussed (Celero 2012; Suzuki 2015). These arguments have been made in pursuit of how to certify Japanese nationality for children born to foreign mothers fathered by Japanese men (Suzuki 2015). Children born to foreign migrant parent(s) without any testimony of a tie to Japanese fathers