5. The possibility for birth registration competent authorities not to be concerned with the child’s residence status 39. A relevant question is whether a registrar will report to the immigration authorities the registration of the birth of a child of an irregular migrant born in the country. If so, it is argued that this possibility may run the risk of discouraging an irregular migrant from registering the birth of their children, making them extremely vulnerable, for example to trafficking. However, in some states, preventing such sharing of information can be construed as an obstacle to effective immigration control. 40. Therefore, attitudes of states differ considerably on this issue. While in a number of states,33 immigration authorities receive information from the civil registry office, in some states34 the registry office does not verify the legality of the stay of the child or its parents in the territory of the state. As a result, the birth certificate does not contain information that would be of interest to immigration control authorities. Identified promising practices In Portugal, the law does not establish reporting requirements and in practice the information on children without residence status is not shared. Although there is no explicit prohibition on sharing information from birth registration with immigration authorities, Article 101-A of the Civil Registration Code requires that medical facilities record birth data in software that can be accessed only by health facilities, the Institute of Registration and Notary Affairs, and the Institute of Social Security. The Portuguese Nationality Act grants Portuguese nationality by birth to children born in the territory if at least one of the foreign parents has resided in Portugal for at least one year, regardless of legal status. The law does not mention any reporting requirements and even offers novel options in terms of proof of stay for those who have resided in Portugal irregularly. In Switzerland, if the domicile details are not proven, the corresponding field remains empty, and the civil registrar refers to the place of residence. If this is not known, no place of residence data is entered, so communication to the migration services is not possible. 33. For example, Lithuania, Netherlands and Slovenia. 34. For example, Azerbaijan, Poland and United Kingdom. Birth registration ► Page 21