In a New York Family Court proceeding when a party does not testify to rebut allegations against him or her the Family Court is permitted "to draw the strongest inference against him as the opposing evidence would allow." This is because the right against self-incrimination and other rights that protect criminal defendants do not extend to Family Court proceedings. So a party can exercise his or her right to remain silent in Family Court. But the Family Court can hold it against them.
Sometimes it still is a good idea to say nothing in Family Court. Any testimony given in Family court can be used against a party in any other court proceeding. This includes a criminal prosecution.
Taking this Family Court rule one step further, a Court may draw a negative inference, or "missing witness" inference, in certain circumstances when a party fails to call a witness.
This rule applies when the following conditions exist. First, the uncalled witness is knowledgeable about a material issue upon which evidence already has been presented at a hearing. Next, the uncalled witness would naturally be expected to provide testimony favorable to the party who has not called him or her. Third, the witness is available to that party. A classic uncalled witness whom may be the subject of this negative inference rule includes the spouse of a party.
A case where I have seen this rule applied was one where the respondent's new wife had mistreated his children. He denied this, but he did not call his new wife as a witness to deny these allegations. We knew that the new wife was knowledgeable about this issue since it involved things she allegedly did and said. It was expected that she would provide testimony favorable to her husband. Third, as his wife she was available to the husband. Hence, this rule applied in that case.
A very important consideration with this rule is that the Court must advise party of the Court's intent to draw an adverse inference. The Court also must give the party the opportunity to establish that the witness is unavailable or to explain the failure to call the witness. Hence, this issue must be raised before the close of the proof in a hearing. So this is an issue that needs to be addressed in advance and an appropriate request made early in the course of the hearing. This is the type of issue that an experienced domestic relations attorney will be able to handle skillfully for litigants.