The opinion of the court was delivered by: Paul L. Abrams United States Magistrate Judge
MEMORANDUM OPINION AND ORDER
PROCEEDINGS Carolyn Demorst ("plaintiff"), on behalf of W.W.G.,*fn1 filed this action on March 26, 2010, seeking review of the Commissioner's denial of W.W.G.'s application for Supplementary Security Income payments. The parties filed Consents to proceed before the undersigned Magistrate Judge on May 12, 2010, and May 25, 2010. Pursuant to the Court's Order, the parties filed a Joint Stipulation on December 22, 2010, that addresses their positions concerning the disputed issues in the case. The Court has taken the Joint Stipulation under submission without oral argument.
BACKGROUND On June 25, 2007, plaintiff filed an application seeking Supplemental Security Income payments for her minor son, W.W.G., alleging that he has been disabled since October 1, 2006, due to attention deficit hyperactivity disorder and asthma. [Administrative Record ("AR") at 101, 110-16, 127-38.] After the application was denied initially, plaintiff requested a hearing before an Administrative Law Judge ("ALJ"). [AR at 102-07.] A hearing was held on September 15, 2008, at which time plaintiff and W.W.G. appeared with counsel and both testified. A medical expert also testified. [AR at 78-100.] A supplemental hearing was held on December 15, 2008, at which time plaintiff appeared with counsel and a different medical expert testified. [AR at 52-77.] On March 4, 2009, the ALJ determined that W.W.G. was not disabled. [AR at 9-17.] When the Appeals Council denied plaintiff's request for review of the hearing decision on January 29, 2010, the ALJ's decision became the final decision of the Commissioner. [AR at 1-6.] This action followed.
STANDARD OF REVIEW Pursuant to 42 U.S.C. § 405(g), this Court has authority to review the Commissioner's decision to deny benefits. The decision will be disturbed only if it is not supported by substantial evidence or if it is based upon the application of improper legal standards. Moncada v. Chater, 60 F.3d 521, 523 (9th Cir. 1995); Drouin v. Sullivan, 966 F.2d 1255, 1257 (9th Cir. 1992).
In this context, the term "substantial evidence" means "more than a mere scintilla but less than a preponderance -- it is such relevant evidence that a reasonable mind might accept as adequate to support the conclusion." Moncada, 60 F.3d at 523; see also Drouin, 966 F.2d at 1257. When determining whether substantial evidence exists to support the Commissioner's decision, the Court examines the administrative record as a whole, considering adverse as well as supporting evidence. Drouin, 966 F.2d at 1257; Hammock v. Bowen, 879 F.2d 498, 501 (9th Cir. 1989). Where the evidence is susceptible to more than one rational interpretation, the Court must defer to the decision of the Commissioner. Moncada, 60 F.3d at 523; Andrews v. Shalala, 53 F.3d 1035, 1040-41 (9th Cir. 1995); Drouin, 966 F.2d at 1258.
EVALUATING DISABILITY IN A CHILD The evaluation of disability for children differs from that for adults. For an individual under eighteen years of age to be disabled for the purpose of receiving benefits, he must suffer from a "medically determinable physical or mental impairment, which results in marked and severe functional limitations, and which can be expected to result in death or which has lasted or can be expected to last for a continuous period of not less than 12 months." 42 U.S.C. § 1382c(a)(3)(C)(i). An impairment meets this requirement if it meets or equals in severity any impairment that is listed in 20 C.F.R. Part 404, Subpart P, Appendix 1 (the "Listing"). 20 C.F.R. § 416.924(d).
A. THE THREE-STEP SEQUENTIAL EVALUATION PROCESS
The Regulations promulgated by the Social Security Administration establish a three-step sequential evaluation process for child disability cases. See 20 C.F.R. § 416.924. At step one, the relevant inquiry is whether the child is engaged in substantial gainful activity. If so, there is no disability, and the claim is denied. 20 C.F.R. § 416.924(b). If the child is not engaged in substantial gainful activity, the fact finder then determines whether the child has a medically determinable impairment or combination of impairments that is severe. If the impairment is a "slight abnormality or a combination of slight abnormalities that causes no more than minimal functional limitations," the Commissioner will find that the impairment is not severe and will deny the child's claim. 20 C.F.R. § 416.924(c). If the child has a severe impairment, the third and final step assesses whether the impairment meets or medically or functionally equals in severity an impairment in the Listing. If the impairment meets or equals the Listing, the child will be found disabled, assuming that the 12-month duration requirement is also met. 20 C.F.R. § 416.924(d).
A child's impairment "is medically equivalent to a listed impairment ... if it is at least equal in severity and duration to the criteria of any listed impairment." 20 C.F.R. § 416.926(a). To establish medical equivalence, "a claimant must establish symptoms, signs and laboratory findings 'at least equal in severity and duration' to the characteristics of a relevant listed impairment." Tackett v. Apfel, 180 F.3d 1094, 1099 (9th Cir. 1999) (quoting 20 C.F.R. § 404.1526).
To determine whether a child's severe impairment functionally equals a listed impairment, the Commissioner assesses all of the functional limitations caused by the child's impairment in six "domains": (1) acquiring and using information; (2) attending and completing tasks; (3) interacting and relating with others; (4) moving about and manipulating objects; (5) caring for oneself; and (6) health and physical well-being. 20 C.F.R. § 416.926a(a), (b). To functionally equal a listed impairment, a child's impairment must result in "marked" limitations in two domains or an "extreme" limitation in one domain. 20 C.F.R. § 416.926a(a). A "marked" limitation is one that "interferes seriously with [the child's] ability to independently initiate, sustain, or complete activities." 20 C.F.R. § 416.926a(e)(2). It is "'more than moderate'" but "'less than extreme.'" Id. A child's "dayto-day functioning may be seriously limited when [his] impairment(s) limits only one activity or when the interactive and cumulative effects of [his] ...