FOR PUBLICATION
 UNITED STATES COURT OF APPEALS
      FOR THE NINTH CIRCUIT

UNITED STATES OF AMERICA,                  No. 06-30597
                Plaintiff-Appellee,
               v.                            D.C. No.
                                          CR-05-00101-RFC
BART LINDEN HOLT,
                                             OPINION
             Defendant-Appellant.
                                      
       Appeal from the United States District Court
               for the District of Montana
       Richard F. Cebull, District Judge, Presiding

                Argued and Submitted
         November 6, 2007—Seattle, Washington

                  Filed December 5, 2007

    Before: William C. Canby, Jr., Susan P. Graber, and
            Ronald M. Gould, Circuit Judges.

                 Opinion by Judge Gould




                           15975
                   UNITED STATES v. HOLT              15977


                        COUNSEL

Cynthia K. Smith, Smith Jasper, P.C., Missoula, Montana, for
the defendant-appellant.

Eric B. Wolff and Marcia Hurd, Assistant United States
Attorneys, Billings, Montana, for the plaintiff-appellee.
15978               UNITED STATES v. HOLT
                         OPINION

GOULD, Circuit Judge:

   Bart Linden Holt appeals his sentence following his guilty
plea conviction for coercing and enticing a minor to engage
in sexual activity in violation of 18 U.S.C. § 2422(b) and pos-
session of child pornography in violation of 18 U.S.C.
§ 2252A(a)(5)(B). We have jurisdiction under 28 U.S.C.
§ 1291, and we affirm the district court’s sentence.

                               I

   On December 7, 2004, as part of an undercover operation,
Federal Bureau of Investigation Special Agent Daniel Vier-
thaler posed as a thirteen-year-old girl in an Internet chat
room. Holt, a then forty-five-year-old podiatrist, contacted
Vierthaler through the Internet chat room, misrepresented
himself as a nineteen-year-old college student, and engaged
Vierthaler’s online persona in sexually explicit conversations.
Over the next six months, Holt continued to contact Vier-
thaler, often discussing the young age of Vierthaler’s online
persona, Holt’s desire to have sexual intercourse with Vier-
thaler’s online persona, and the fact that Holt would be crimi-
nally liable if he engaged in sexual intercourse with a minor.

   On June 21, 2005, more than six months after his first con-
tact with Vierthaler, Holt revealed his true age to Vierthaler,
and on July 12, 2005, Holt revealed his true identity. On two
separate occasions, on July 26 and 27, 2005, Holt transmitted
to Vierthaler webcam footage of himself masturbating to the
point of ejaculation. Throughout July of 2005, Holt made
arrangements for a sexual encounter with Vierthaler in Bil-
lings, Montana. On August 1, 2005, Holt traveled from Mis-
soula to Billings to have sexual intercourse with Vierthaler.
After Holt arrived at the meet site, he was approached by law
enforcement. He attempted to flee but was apprehended.
                    UNITED STATES v. HOLT                 15979
   A subsequent search of Holt’s computers uncovered images
of child pornography that he had downloaded from the Inter-
net, including images of the sexual penetration of very young
children. Holt later admitted to engaging in other similar con-
versations with a girl in Great Falls, also using his webcam to
transmit sexually explicit images of himself to her.

   On August 19, 2005, a federal grand jury indicted Holt. On
July 13, 2006, Holt pleaded guilty to coercing and enticing a
minor to engage in sexual activity in violation of 18 U.S.C.
§ 2422(b) and possession of child pornography in violation of
18 U.S.C. § 2252A(a)(5)(B).

   The presentence report (“PSR”) prepared in accordance
with Holt’s guilty plea calculated the base offense level for
his coercion and enticement violation at 24 and applied two
enhancements, a two-level enhancement for misrepresentation
of identity pursuant to U.S.S.G. § 2G1.3(b)(2)(A) and a two-
level enhancement for use of a computer pursuant to U.S.S.G.
§ 2G1.3(b)(3)(A), to reach an adjusted offense level of 28.
The PSR calculated the base offense level for Holt’s posses-
sion of child pornography violation at 18, with five enhance-
ments, including a two-level enhancement for minors under
the age of twelve pursuant to U.S.S.G. § 2G2.2(b)(2), a four-
level enhancement for sadistic or masochistic conduct pursu-
ant to U.S.S.G. § 2G2.2(b)(4), and a two-level enhancement
for vulnerable victim pursuant to U.S.S.G. § 3A1.1(b), mak-
ing the adjusted level for this offense 33. Holt received a
three-level deduction for his early acceptance of responsibility
and timely notification of plea, making Holt’s total offense
level 31 and his final guideline range 121 to 151 months.

   On November 2, 2006, Holt appeared for sentencing and
objected to the advisory guideline calculation on two grounds.
First, Holt argued that the district court improperly applied a
two-level enhancement for knowing misrepresentation of
identity pursuant to U.S.S.G. § 2G1.3(b)(2)(A). Holt admitted
that he initially misidentified himself as a nineteen-year-old
15980               UNITED STATES v. HOLT
college student but contended that, because he revealed his
true name and age before sending Vierthaler webcam footage
of his masturbation and before traveling to Billings to meet
with Vierthaler, he had not misrepresented his identity in
order to coerce or entice a minor to engage in sexual activity.
The district court overruled this objection, finding that Holt
initiated the online conversations in December of 2004 and
did not reveal his true age until after he had engaged in six
months of “grooming what he thought was a 13-year old
minor.”

   Holt’s second objection was to the vulnerable victim
adjustment contained in U.S.S.G. § 3A1.1(b). Holt argued that
the district court would be double counting if it applied the
four-level enhancement for the sadistic or masochistic nature
of some of the images and the two-level enhancement for vul-
nerable victim based on the small size of the victims and the
pain they must have experienced due to the sexual penetra-
tion. The district court overruled Holt’s objection, supporting
its decision with the young age of the children, our holding in
United States v. Wright, 

(9th Cir. 2004), and
Holt’s occupation as a doctor, which provided him with spe-
cialized knowledge of human anatomy.

   On November 7, 2006, the district court sentenced Holt to
120 months’ imprisonment and fifteen years of supervised
release. Holt timely appealed his sentence.

                              II

   We review de novo the district court’s interpretation of the
United States Sentencing Guidelines (“the Guidelines”),
review for clear error the district court’s factual determina-
tions, and review for abuse of discretion the district court’s
applications of the Guidelines to the facts. United States v.
Kimbrew, 

, 1151 (9th Cir. 2005).
                     UNITED STATES v. HOLT                 15981
                              III

   [1] Holt opposes the district court’s enhancement of his
sentence on two grounds. First, Holt contests the district
court’s application of a two-level enhancement for misrepre-
sentation of identity to the base level of his coercion and
enticement offense. The Guidelines suggest applying this
enhancement if “the offense involved the knowing misrepre-
sentation of a participant’s identity to persuade, induce,
entice, coerce, or facilitate the travel of, a minor to engage in
prohibited sexual conduct.” U.S.S.G. § 2G1.3(b)(2)(A). Holt
argues that the enhancement was improperly applied to his
base offense level because he revealed his true age and iden-
tity before engaging in any unlawful conduct. We hold, how-
ever, that the district court properly applied the two-level
enhancement because Holt initially identified himself as a
nineteen-year-old college student and revealed his true age
and identity only after more than six months of sexually
explicit Internet chats with an undercover officer who had
portrayed himself in his online persona as a thirteen-year-old
girl. The district court reasonably could have concluded that
Holt was misrepresenting his identity in a prolonged effort to
groom what he thought was a thirteen-year-old girl for illicit
sexual contact.

   Second, Holt challenges the district court’s enhancement of
the base level of his possession of child pornography offense
by application of, among other enhancements, a two-level
enhancement for vulnerable victim pursuant to U.S.S.G.
§ 3A1.1(b) and a four-level enhancement for the sadistic or
masochistic conduct portrayed in the images pursuant to
U.S.S.G. § 2G2.2(b)(4). Holt argues that the district court
improperly “double counted” by applying both enhancements
for essentially the same harm—namely, the extreme pain that
necessarily would have been experienced by a very young
child depicted in the pornography as being sexually pene-
trated.
15982                  UNITED STATES v. HOLT
   [2] “Impermissible double counting occurs when one part
of the Guidelines is applied to increase a defendant’s punish-
ment on account of a kind of harm that has already been fully
accounted for by application of another part of the Guide-
lines.” United States v. Nagra, 

, 883 (9th Cir.
1998) (internal quotation marks omitted). However, “[d]ouble
counting is not always impermissible; it is sometimes autho-
rized and intended by the Sentencing Guidelines when each
invocation of the behavior serves a unique purpose under the
Guidelines.” United States v. Syrax, 

, 428 (9th
Cir. 2000) (internal quotation marks omitted).

   [3] We have previously held that a district court can apply
the sadistic conduct enhancement any time images portray the
penetration of prepubescent children by adult males because
such images are necessarily pleasurable for the participant and
painful for the child. United States v. Rearden, 

,
614-15 (9th Cir. 2003). Here, it follows even more strongly
that the district court properly applied the enhancement where
at least one image in Holt’s possession depicted the penetra-
tion of a two- or three-year-old child by an adult male.

   [4] A district court can apply the vulnerable victim
enhancement where a child is so young and small that he or
she is less able to resist than other child victims of pornogra-
phy and will experience greater pain from sexual penetration.
See 

(holding that the district
court’s application of both the enhancement for children
under twelve and the enhancement for vulnerable victim did
not constitute improper double counting). Although Holt
argues that we should distinguish Wright on the ground that
the victim in Wright was an infant, whereas here a toddler vic-
tim could have walked away,1 that argument is so weak as to
  1
   “[T]he victim in Wright was 11 months old and therefore unable to
walk or talk. The victims who the District Court found to be vulnerable
in Mr. Holt’s case were two to three years old and presumably able to
walk and talk.”
                    UNITED STATES v. HOLT                15983
be frivolous. There can be no serious dispute that the two- or
three-year-old child shown being sexually penetrated in the
pornography was not in a position of sufficient strength to
resist the sexual abuse.

   [5] Both the sadistic conduct and vulnerable victim
enhancements account for the pain experienced by a young,
small victim of child pornography, but the enhancements also
account for distinct characteristics of the crime: the sadistic
conduct enhancement accounts for the pleasure necessarily
experienced by the perpetrator, while the vulnerable victim
enhancement accounts for the inability of the victim to resist
sexual abuse. Because the two enhancements account for
these distinct wrongs, it was proper, and no abuse of discre-
tion, for the district court to apply both to the challenged
criminal conduct. See 

.

  AFFIRMED.