This paper presents the first investigation of English-speaking children's comprehension of copy-raising structures with an experiencer (e.g., John seems to Bill like he is happy) and shows that children have similar difficulty with copy-raising as with standard raising. To explain the acquisition of both structures, a unified account is proposed that attributes their difficulty to the Performance-based Intervention Effects (rather than to a grammatical deficit). A Truth-Value Judgment Task (Crain & Thornton, 1998) was conducted with a total of 22 native English-speaking children (age 3;10 to 5;3, mean=4;8). Three types of sentences were used, balanced for true and false answers: (1) unraised control items (e.g., It seems to Mickey like Donald is short), (2) CR items with Gender Mismatch, in which the experiencer and the pronominal copy are of different genders (e.g., Bart seems to Lisa like he is studying), (3) CR items with Gender Match, in which the experiencer and the pronominal copy are of the same gender (e.g., Donald seems to Mickey like he is short). The results show that children have difficulty comprehending CR sentences with an intervening experiencer when there is no gender cue available to help them correctly interpret the referent of the pronominal copy (i.e., CR-Gender Match condition). These results are interpreted as evidence for a generalized intervention analysis of raising (Choe, 2012; cf. Orfitelli, 2012), in which an intervening nominal (in this case the experiencer) causes parsing difficulties which result in degraded comprehension. Such effects have been observed in many other patterns (e.g., wh-questions, relative clauses, coordinate constructions, etc.), thus reducing the observed difficulty with raising and CR sentences to a non-grammatical parsing difficulty.