From the 2002 General Instruction of the Roman Missal (GIRM) approved for the USA, which can be accessed from
romanrite.com/girm.html :
“60. The reading of the Gospel is the high point of the Liturgy of the Word. The Liturgy itself teaches that great reverence is to be shown to it by setting it off from the other readings with special marks of honor: whether the minister appointed to proclaim it prepares himself by a blessing or prayer; or the faithful,
standing as they listen to it being read, through their acclamations acknowledge and confess Christ present and speaking to them; or the very marks of reverence are given to the Book of the Gospels.”
The 1973 Directory for Masses with Children has:
“42. With regard to the number of readings on Sundays and feast days, the decrees of the conferences of bishops are to be observed. If three or even two readings appointed on Sundays and weekdays can be understood by children only with difficulty, it is permissible to read two or only one of them, but the gospel reading should never be omitted.” This is in the section “Masses with Children in Which Only a Few Adults Participate”. But with a bishop’s permission it can also apply to “Mass with Adults in Which Children also Participate” (n. 19).
From the 2002 GIRM: “32. Special celebrations of Mass should observe the guidelines established for them: … for Masses with children, cf. Sacred Congregation for Divine Worship, Directory for Masses with Children, 1 November 1973: AAS 66 (1974), pp. 30-46;”
I don’t know if the United States Conference of Catholic Bishops has made any decrees that effect this.