A couple of weeks ago, the 7th District Court of Appeals (Amarillo) reaffirmed the legal principle that:
Expert testimony that a child did not exhibit indications of coaching or manipulation [does] not to constitute an opinion on the child's truthfulness.In Cantu v. State, one of the defense theories was that the child victim had been coached by her mother to make false allegations against Appellant. To counter this theory, the State brought an experienced child interviewer from the Advocacy Center to testify that in her expert opinion, the child victim in this case did not exhibit any "red flags" that would indicate that she had been coached or manipulated. The State was careful not to elicit testimony that the victim was being truthful and thus, the conviction was affirmed on appeal.
To me, this is still an area ripe for objections at trial and a special inclusion in the jury charge. You may get a judge that will exclude it. Okay, probably not, but it's worth a shot. While most lawyers can see the technical difference between an opinion on truthfulness and an opinion on coaching, many jurors will not.
You can read the opinion here.