Liam Adams was convicted on Tuesday of abusing his daughter over a six-year period. It began when she was four.
Speaking in Dublin, Gerry Adams was asked a number of times why he did not report his brother to the authorities.
He said: "The police were aware over 20 years ago and there is a lot of disinformation being flung about".
He added: "But let me say this, this has been and continues to be a huge ordeal for my family - we're a very large family - especially for Áine, but for all members of my family.
"And I think people need to be given the space to come to terms with all of that.
"And if it was your family, you would want the same respect and space and privacy on these matters."
The Sinn Féin president made his first report to the police about the allegations in 2007, shortly after his party voted to accept the Police Service of Northern Ireland.
In 2009, Gerry Adams made a second statement to police, telling officers that his brother Liam had confessed to him nine years earlier, in 2000,  that he had sexually abused his daughter Áine.
Northern Ireland's first minister, Peter Robinson, was asked on Wednesday whether Gerry Adams has questions to answer following the conviction of his brother.
Mr Robinson expressed his sympathy to the victim, who, he said, "has waited so long for justice" and said it is up to the authorities to determine if anyone else has questions to answer.
He said he did not want to "make politics out of a very sad situation".
The Sinn Féin President Gerry Adams has spoken about the child abuse suffered by his niece Áine, who was sexually assaulted by her father Liam Adams.