Until October 1, 1998, Dutch passports were issued only to children who were adopted in the Netherlands, the Dutch Antilles or Aruba . The possibilities were extended when The Hague Adoption Convention of 1993 came into force .
From October 1, 1998, minor children who were adopted outside of the Netherlands in accordance with this Convention would be themselves, legally Dutch if at least one of the adoptive parents is Dutch. This applies only to 'strong' adoptions. 
Conflict Of Laws
With the implementation of the Conflict of Laws on Adoption Act, from January 1, 2001, minor –aged adopted children could also obtain Dutch nationality in recognized foreign adoptions, in which The Hague Adoption Convention 1993 is not applicable, if one or more of the adoptive parents is Dutch and it is considered to be a 'strong' foreign adoption. Minor-aged children, who live outside of the Netherlands together with their adoptive parents, during the adoption application and decision process, may automatically become Dutch citizens if the foreign adoption decision is legally recognized . Minor-aged children, who are adopted outside of the Netherlands by at least one Dutch parent in possession of principle consent, can become Dutch as soon as the Dutch court recognizes the foreign adoption .
In the case of a so-called ”weak” adoption , the minor-aged child may only become a Dutch national when the Dutch court has converted the adoption into an adoption in accordance with Dutch law . In all of these cases, the minor-aged adoptive child would only become Dutch when the (foreign) adoption decision reaches the stage of ‘final judgment’ .
Children who were adopted in a foreign country, basically, were left behind, before the Dutch Nationality Act was changed by the implementation of first The Hague Adoption Convention of 1993 and later the Conflict of Laws on Adoption Act. Without an order from the Dutch court, Dutch nationality could not be granted to a foreign adoptee. That was clear from two rulings by the Supreme Court.
Ghanese orphan adopted by aunt
The case in which the Supreme Court made a ruling on February 1, 2008 , is that of an unmarried, under-aged Ghanaian mother who become pregnant by unknown father. She died in childbirth in 1980. The orphan was adopted according to local law, by the mother’s Ghanaian sister and became part of the aunt’s clan. This Ghanaian woman, adoptive mother/aunt, was married in 1982, to an Arubian man with Dutch nationality, which was granted to her in 1982. From January 1, 1985 to January 1, 1988, Dutch women were given the opportunity to choose for Dutch nationality for their adopted chidren. This statutory provision also included children who were adopted 'in the Netherlands, the Dutch Antilles or in Aruba”. The Ghanaian woman chose Dutch citizenship for her child on September 10, 1986. She did not indicate that her child was adopted.
In 2003, the birth certificate of the adopted child was investigated. The Dutch authorities discovered that this was a child who was adopted in Ghana, not the biological child of the Ghanian woman. They held the position that the child was never Dutch, because at the time of the adoption request, in 1986, the legal requirements were not met. Furthermore, the child was not adopted in the Netherlands, the Dutch Antilles or Aruba.
The child complained, in particular, that adopted children in a situation such as this, have the right to obtain (Dutch) nationality from the person by whom they were brought up or with whom they form a family, under Article 8 of the European Convention for the Protection of Human Rights and Fundamental Freedoms (ECHR) . The Supreme Court denied this, arguing that although protection under the ECHR can be founded on the familial bond between parents their adopted children; nowhere in Article 8 of the ERHC or in any other article of the ERHC is there a provision granting the right to any nationality. The Supreme Court emphasized that as far as family life between a foreign national and a Dutch national is concerned, the Netherlands is free to correlate it with nationality rights, or not.
Somalian children adopted by older half-brother
The Supreme Court ruled on a case on May 25, 2012, in which a Somali man fled to the Netherlands in 1992. He was admitted as a refugee. Three minor-aged children followed later, brought into the country in the context of family reunion with the Somali man, their half-brother. However, he declared them to be his own children. In 1997, the man became a naturalized Dutch citizen. The three minor-aged children shared in the naturalization, since the Dutch authorities believed them to be the man’s sons.
On February 14, 2006, the family was filmed for a tv program called Network. From this show, it came to light that the three were not his children, but rather that he was their much older half-brother. The Dutch authorities informed the children that they have never been Dutch citizens, as only ones “own” children are allowed to be co-naturalized. The children did not agree and argued that they were raised by their half-brother and cared for as his “own” children and should be considered to be the Somali man’s adopted children. Therefore, they had rightly shared his naturalization with him. The particular family situation with these children at the time the Somali man was naturalized, however, was not recognized. They were a part of their half-brother and his wife’s family, who raised them and cared for them as their own, along with their own child. The formal conditions set out, for adoption as are stated in Art. 11, par. 12 of the (old) Dutch Nationality Act, interfer with family life on the grounds of Article 8, par. 2 of ECHR.
On that basis, the children launched an appeal to a ruling by the European Court of Justice in the case of Rottmann / Freistaat Bayern . In that case, the Court considered that in the context which tests proportionality, what must be determined is whether the loss of nationality, coupled with the loss of European citizenship, is justified in light of the severity of the fraud committed (in the case of Mr. Rottman), the lapsed time between the naturalization decision and its revocation and the possibilities for the person to re-acquire his original nationality. In other words, the loss of a persons nationality must not be disproportionate with respect to the special circumstances that might play a role in a particular case.
The Surpreme Court upheld their decision of February 1, 2008, that neither Article 8 of ECHR, nor in any other provisions in the ECHR is there any foundation for granting the right to any nationality. The children were not co-naturalized with their half-brother because they did not fulfill the legal requirements. With regard to the comparison to the case of Rottmann/Freistaat Bayern, the Supreme Court stated that the case involved a naturalized German man who originally had Austrian nationality. When his German nationality was revoked, he also lost his European Union citizenship rights (upon acquiring German nationality, Mr. Rottman lost his Austrian nationality, as is according to Austrian national law). This case is not comparable to that of the Somali children because Dutch nationality was never granted and they came from Somalia and thus, were never European Union citizens.
International adoption law plays, foremost, a clear role in establishing the Dutch nationality of an adopted child. Can the foreign adoption be recognized in Netherlands or not? Do the Dutch courts have to make a new ruling regarding the adoption? Will the adopted child still be minor-aged at that time? The frustrating thing is that even if the foreign adoption were to be recognized in the Netherlands, it does not automatically mean that the adopted child will be Dutch.
In conclusion, a note about the opposite situation: can adopted children keep their own nationality after they’ve been adopted or not? The Dutch State has absolutely no influence on this, except at the diplomatic level. The answer depends on nationality laws of the child’s country of origin. Children from Brazil, for example, do not lose their Brazilian nationality through adoption, because Brazil nationality law has determined it to be so. China does not recognize dual nationality, therefore, Chinese children adopted by Dutch parents would always lose their Chinese nationality. It would, therefore, be pointless for adopted children to appeal to the Dutch authorities in an attempt to keep their original nationality.