The rights which a child acquires by adoption are those and only those declared by legislative act. The adoption statute in effect when Mr. Andrews died may be found in G.S. (1943 edition) 48-23. If appellants had been adopted prior to Mr. Andrews’ death, the statute then in effect would not have conferred on appellants the right to participate in the distribution of his estate; nor would they, by reason of the statute, have qualified as great nieces and great nephews of testator, Grimes v. Grimes, 207 N.C. 778, 178 S.E. 573; Barton v. Campbell, 245 N.C. 395, 95 S.E. 2d 914; nor would they, by any of the adoption laws enacted prior to 1963, have qualified, as heirs or distrib-utees of Mr. Andrews, nor as his great nieces and great nephews, entitled to take under his will. Thomas v. Thomas, 258 N.C. 590, 129 S.E. 2d 239; Allen v. Allen, 260 N.C. 431, 132 S.E. 2d 909.
The 1963 Legislature, by c. 967, S.L. 1963, rewrote G.S. 48-23. That Act, ratified June 18, 1963, by express provision, became effective from and after its ratification. The provisions of the 1963 Act, pertinent to *536the decision of this case, are the concluding sentence of subsection (a), and subsection (c). The last sentence of subsection (a) reads: “An adopted child shall have the same legal status, including all legal rights and obligations of any kind whatsoever, as he would have had if he were born the legitimate child of the adoptive parent or parents at the date of the signing of the final order of adoption, except that the age of the child shall be computed from the date of his actual birth.” Unless subsection (c) requires a different rule, this change would operate prospectively and would have no application to vested estates. Bennett v. Cain, 248 N.C. 428, 103 S.E. 2d 510.
Subsection (c) provides: “From and after the entry of the final order of adoption, the words ‘child’, ‘grandchild’, ‘issue’, ‘descendant’, or an equivalent of the plural forms thereof, or any other word of like import in any deed, grant, will or other written instrument shall be held to include any adopted person, unless the contrary plainly appears by the terms thereof, whether such instrument was executed before or after the entry of the final order of adoption and whether such instrument was executed before or after the enactment of this Act.”
, Sec. 17, Art. I, of the Constitution of North Carolina, and Sec. 1 of the Fourteenth Amendment to the Constitution of the United States, forbid the Legislature from diminishing a vested interest by artificially increasing 'the class in which the estate has vested. Here, the trust estate vested in the brothers, the sister, the nieces and nephews, eleven in number, and the great nieces and great nephews, twelve in number, living on October-21, 1946, the day testator died, G.S. 31-41. Parker v. Parker, 252 N.C. 399, 113 S.E. 2d 899; Hummell v. Hummell, 241 N.C. 254, 85 S.E. 2d 144. If G.S. 48-23, as amended in 1963, is construed to make a child adopted by a niece or nephew of Mr. Andrews, subsequent to 1946; his great niece or great nephew, and thereby entitled to participate in the trust he created, it unconstitutionally diminishes the estate given to the natural born children of nieces and nephews and is void. Robinson v. Barfield, 6 N.C. 391; Hoke v. Henderson, 15 N.C. 1; O’Connor v. Harris, 81 N.C. 279; Booth v. Hairston, 193 N.C. 278, 136 S.E. 879; Bateman v. Sterrett, 201 N.C. 59, 159 S.E. 2d 14.
Appellants do not contend the Legislature could enact a statute diminishing the share vested in a beneficiary by artificially increasing the number of beneficiaries. Their position is: Mr. Andrews had the legal right to make adopted great nieces and great nephews beneficiaries of his estate, just as he had the right to make natural born great nieces and great nephews beneficiaries of his estate; and if, when he wrote his will, he meant to include within the words “great niece” or “great nephew,” one thereafter adopted by a niece or nephew, the person so adopted would participate equally with a child born naturally *537to a niece or nephew. It is quite true that the words “great niece” and “great nephew” would, if Mr. Andrews so intended, when he wrote the will, have included all who became a great niece or a great nephew by adoption or by birth. Bradford v. Johnson, 237 N.C. 572, 75 S.E. 2d 632; Barton v. Campbell, supra.
Appellants interpret the 1963 Act not as divesting a vested estate, but as creating a presumption that the words “great niece” and “great nephew” were understood by testator, when he wrote his will, to include both natural born and adopted children, thereby imposing on the natural born great nieces and great nephews the burden of showing that the words “great niece” and “great nephew” did not include one adopted by a niece or nephew, but only one born to a niece or nephew.
This interpretation of the statute, they argue, would not do violence to either State or Federal Constitutions, since the statute, so interpreted, would merely create a rule of evidence to be used in ascertaining intent — a power which the Legislature may constitutionally exercise. Spencer v. Motor Co., 236 N.C. 239, 72 S.E. 2d 598; State v. Griffin, 154 N.C. 611, 70 S.E. 292; Prince v. Nugent, 172 A. 2d 743. The power of the Legislature to create presumptions is not unlimited. The presumption, or inference to be drawn from a given set of facts must have some reasonable relation to the stated inference. State v. Griffin, supra; Bailey v. Alabama, 219 U.S. 219, 55 L. Ed. 191; Tot v. United States, 319 U.S. 463, 87 L. Ed. 1519; Anno. 162 A.L.R. 495-535. The power to create a presumption can not be made a device to short circuit constitutional prohibitions.
It is the duty of the Court when interpreting a will to give effect to a testator’s intention. When that intent can be ascertained with assurance from the words used, there is no need for presumptions or extrinsic evidence. Yount v. Yount, 258 N.C. 236, 128 S.E. 2d 613; Stellings v. Autry, 257 N.C. 303, 126 S.E. 2d 140; Morris v. Morris, 246 N.C. 314, 98 S.E. 2d 298; Trust Co. v. Wolfe, 243 N.C. 469, 91 S.E. 2d 246; Trust Co. v. Green, 239 N.C. 612, 80 S.E. 2d 771.
In deciding this case, it is not necessary to fathom legislative intent. The Legislature made it abundantly clear that the Act did not apply to instruments in which it clearly appeared testator did not intend for an adopted child to stand on the same footing with a blood relative.
Judge Carr was of the opinion that Mr. Andrews’ will did not clearly indicate testator’s intent to exclude adopted children from the trust he created. We reach a different conclusion. The persons specifically named in the will as beneficiaries of the trust, twenty-six in number, were all natural born. They were blood relatives of testator. This number could be increased only if great nieces or great nephews were born within twenty-one years after testator’s death. Birth is, by the express pro*538visions of subsection (i) of item 2, and subsection (b) of item 6, made a condition precedent to participate in the trust. Born to whom, one may inquire? The answer, of course, is to a niece or nephew of the testator. Birth is not synonymous with adoption.
Holding, as we do, that the 1963 Act, by its express, language, excludes from its provisions those trusts or estates where it clearly appears that the beneficiaries are to be the natural born, and not adopted children, it follows that the judgment must be, and is,
Affirmed.