The defendant assigns error to the court’s failure to submit the (f)(7) mitigator, “The age of the defendant at the time of the crime.” N.C.G.S. § 15A-2000(f)(7). The court was required to submit to the jury any statutory mitigating circumstances which the evidence would support regardless of whether the defendant objects to it or requests it. State v. Lloyd, 321 N.C. 301, 312, 364 S.E.2d 316, 324, sentence vacated on other grounds, 488 U.S. 807, 102 L. Ed. 2d 18 (1988).
In interpreting the (f)(7) mitigator, we have held that chronological age is not the determinative factor. We have said age is a flexible and relative concept. “The defendant’s immaturity, youthfulness, or lack of emotional or intellectual development at the time of the crime must also be considered.” State v. Bowie, 340 N.C. 199, 203, 456 *217S.E.2d 771, 773, cert, denied, 516 U.S. 994, 133 L. Ed. 2d 435 (1995); see State v. Johnson, 317 N.C. 343, 393, 346 S.E.2d 596, 624 (1986); State v. Oliver, 309 N.C. 326, 372, 307 S.E.2d 304, 333 (1983).
In State v. Holden, 338 N.C. 394, 450 S.E.2d 878 (1994), we held that the age circumstance should have been submitted to the jury where there was substantial evidence showing that despite the defendant’s being thirty years old, his mental age was ten years and his problem-solving skills were closer to those of a ten-year-old. Id. at 407-08, 450 S.E.2d at 885.
In this case, the defendant presented evidence from Dr. Puente and Dr. Lara that was at least as substantial as that offered in Holden. Dr. Puente testified that the defendant has a history of mild to moderate mental retardation and organic brain syndrome of moderate range. On one IQ test administered by Dr. Puente, the defendant scored a 56, signifying an intellectual age of 7.4 years. He administered numerous other tests, all of which indicated that the defendant is impaired. Dr. Puente was of the opinion that the defendant was impaired at the time he committed the murder and rape and that the defendant’s ability to appreciate the criminality of his conduct and his ability to conform to the requirements of the law were impaired at the time of the crime.
Dr. Puente’s testimony was supported by Dr. Lara’s testimony, who testified that the defendant suffered from mild mental retardation and that his performance on tests indicated evidence of chronic brain damage. The defendant scored a 64 on an IQ test administered by Dr. Lara. Dr. Lara concluded that the defendant’s mental condition significantly restricted his ability to conform his actions to the limits established by the law.
The testimony of Dr. Puente and Dr. Lara constitutes substantial evidence that would support a finding by the jury that the defendant’s age at the time of the crime was mitigating. Therefore, the trial court was required to submit the (f)(7) statutory mitigating circumstance to the jury. See id. at 407, 450 S.E.2d at 885.
This Court has repeatedly held that the failure to submit to the jury a statutory mitigating circumstance that is supported by the evidence is reversible error, unless the State can prove the failure to submit was harmless beyond a reasonable doubt. State v. Wilson, 322 N.C. 117, 145, 367 S.E.2d 589, 605 (1988). The State argues that the jury considered the evidence concerning the defendant’s mental age *218when it weighed the (f)(2), (f)(6), and the nonstatutory mental retardation mitigating circumstances, and that it is clear that the jury would still have returned a sentence of death. We disagree. The State’s argument ignores the fact that each statutory mitigating circumstance must be given individual weight, if found to exist. See State v. Greene, 329 N.C. 771, 776-77, 408 S.E.2d 185, 187 (1991). Furthermore, the submission of nonstatutory mitigating circumstances that parallel statutory mitigating circumstances does not satisfy the State’s burden of showing harmlessness beyond a reasonable doubt because the jury was not required to give mitigating value to the nonstatutory mitigating circumstances. See State v. Quick, 337 N.C. 359, 364, 446 S.E.2d 535, 538 (1994). Thus, the failure to submit the (f)(7) mitigating circumstance was prejudicial error.
The defendant made several other assignments of error which we do not discuss because the questions they raise may not recur at a new sentencing proceeding.
For the reasons stated above, the defendant is entitled to a new capital sentencing proceeding.
NEW SENTENCING PROCEEDING.