Proof of Filiation

Someone asked me, "I have a friend who...  

was born out of wedlock (between an already married man and his mistress). His name is John. He also has a sister, Jane (also born out of wedlock between the same married man and his mistress). John and Jane were taken in by the father and the father’s legal wife but were never legally adopted. The father and the wife already have two daughters and one son. Both John and Jane have lived together with the father and the rest of the family for more than ten years. 

If the father, with no will, were to lose his life in a sudden car accident, how will his assets be divided among his children? May John and Jane receive any inheritance if the wife of the father deny John and Jane were her husband’s illegitimate children and that the father had not left a will? 

My answer is

John and Jane shall be entitled to half of what the legitimate children gets. They can prove their filiation just by using the father name in the birth certificate or some other handwritten instrument of the father to John or Jane.

In this case, the wife is estopped from questioning the paternity of her husband since they had taken cared of the kids together for more than 10 years. It would be the burden of the wife to prove that she was not aware that John and Jane were the children of her husband yet she took them in for 10 years.

So the division will be half of all properties will be given to the wife as her conjugal share. The balance will be divided as follows:

3 Legitimate Chidren x 2 = 6
1 Surviving Spouse x 2    = 2
2 Illegitimate  x 1                2
Denominator is                    10

So John and Jane is entitled to 1/10 of the estate of their father after dividing conjugal shares.