Does the statute require proof that the defendant knew the individual transported had not attained the age of 18 years?

QUESTION PRESENTED The crime of Transportation with Intent to Engage in Criminal Sexual Activity under 18 U.S.C. 2423(a) reads: A person who knowingly transports an individual who has not attained the age of 18 years in interstate or foreign commerce, or in any commonwealth, territory or possession of the United States, with intent that the individual engage in prostitution, or in any sexual activity for which any person can be charged with a criminal offense, shall be fined under this title and imprisoned for not less than 10 years or for life. Does the statute require proof that the defendant knew the individual transported had not attained the age of 18 years? Does the statute require proof that the dominant purpose of the trip was to take a minor across state lines to engage in prostitution, or other criminal sexual activity?