Beneficiaries and their blood relations to the fourth degree may not be witnesses. Nuncupative wills are not recognized. Soldiers' and sailors' wills are subject to special rules as in most other countries. Full freedom of testation only exists when the testator has no ascendants or descendants, otherwise the disposable portion of his estate is constrained by the rules of forced heirship: if the testator has one child he may only dispose of half his estate, if two only one-third, if three or more only one-fourth; if he has no descendants but ascendants in both lines he may dispose of half, if ascendants in one line only he may dispose of three-fourths. The full age of testamentary capacity is 21 years, but minors over the age of 16 may dispose by will of half of the estate of which they could dispose had they been of full age. There is no restriction against married women making wills. Will substitutes such as will contracts or a "pactum successorium" (aka contract concerning succession) are invalid (art. 791 FrCC).