For multiple births or simultaneous adoptions
Regulations: Art. 4.2 Text Recast of the legal provisions of the Community of Castilla y León regarding own and assigned taxes, approved by Legislative Decree 1/ 2013, September 12.
The 50 per 100 of the amount corresponding to the application of the deduction for birth or adoption if the multiple birth or simultaneous adoption involved two children that generate the right to the application of the " minimum per descendant ".
The 100 per 100 of the amount corresponding to the application of the deduction for birth or adoption, if the multiple birth or simultaneous adoption has been three or more children, which generate the right to the application of the "minimum per descendant ".
The same deduction will be made in the cases of independent births or adoptions that occur in a period of twelve months .
In the case of the birth of two children within a period of twelve months, one in 2020 and the other in 2021, only the parents who live with the children in 2020 and 2021 may apply the deduction.
Additional deduction for multiple births or simultaneous adoptions produced in 2019 and/or 2020
901 euros during the two years following the last birth or adoption that is computed for the purposes of understanding multiple births or simultaneous adoption that gives the right to apply the deduction.
Requirements and other conditions for the application of the deduction
Regulations: Art. 10 Consolidated Text of the legal provisions of the Community of Castilla y León regarding own and assigned taxes.
In order to apply this deduction the total tax base (boxes [ 0435] and  of the declaration) minus the personal and family minimum (box  of the declaration) cannot exceed the following amounts:
For the purposes of determining the order number of the born or adopted child , the born child and the remaining children, of either of the two parents, who live with the taxpayer in the date of accrual of the tax (normally, December 31), counting for these purposes both those that are by nature and by adoption.
When both parents or adopters are entitled to the application of the deduction, its amount, in the case of individual declaration, will be prorated in equal parts in the declaration of each of them.
If only one of the spouses has the right to the deduction, because the other exceeds the tax base limits less the personal and family minimum required, the deduction applicable to the spouse will be half of the total amount. Half of the total amount of the deduction will also correspond to the taxpayer whose spouse has not resided in the Community of Castilla y León in 2021.
In the event that a multiple birth or simultaneous adoption had occurred during the 2020 period, and those born in said year were not part of a new multiple birth along with a child born in the 2021 period, the deduction amount must be entered. additional amount of 901 euros (prorated based on the number of taxpayers entitled to it) in the corresponding box, as long as the income limit requirement is met.
In the event that the taxpayer does not have sufficient full autonomous quota to apply the total deduction in the tax period in which the right to it is generated, the amount not deducted may be applied in the three tax periods following until the total amount of the deduction is exhausted, if applicable.
Note: Taxpayers who have not exhausted the entire deduction both in the tax period in which the right to it is generated and in the three following periods, may request payment of the remaining amount to be applied.
This deduction is compatible with the deduction for birth or adoption regulated in the previous article.