McDonald supports Adams's stance on Jean McConville
Ms McDonald said she did not believe the remarks by Mr Adams, made during an interview on US broadcaster CBS, were an attempt to be "flippant".
And she claimed "awful things happened" during the conflict, when asked whether she agrees with Mr Adams.
"The truth is, in the course of the conflict, awful things did happen. They happened on all sides," Ms McDonald said.
"The last thing any of us would like to do is compound the hurt of the McConville family or any family. What happened to Jean McConville was utterly wrong and indeed the other families of the Disappeared," she added.
Asked by CBS interviewer Scott Pelley "how do you orphan 10 children, what kind of depravity is that?", Mr Adams responded: "That's what happens in wars, Scott. That's not to minimise it. That's what American soldiers do, Irish republican soldiers do, you know. That's what happens in every single conflict."
The McConville family have expressed their hurt over Mr Adams's comments, insisting the murder was "ordered and planned".
During the interview, Mr Adams also denied that he had ever ordered a murder, planted a bomb or pulled a trigger.
Asked whether his hands are "clean", Mr Adams replied; "Well it depends. That's an evocative term."
Ms McConville is one of the most well-known murder victims of The Troubles.
She was dragged away from her home at Divis Flats, Belfast by an IRA gang of up to 12 men and women after being accused of passing information to the British army in Belfast.
An investigation later carried out by the Northern Ireland Police Ombudsman rejected the allegations. Separately yesterday, Mr Adams revealed that he intends to call for a referendum on Irish unity.
He did not give an indication of when the call will be made, but said that next year's centenary events "should be a catalyst for a national debate" on unity.
"Partition has retarded and distorted the political, social and economic life of this island," the Sinn Féin president said.
During a 1916 commemoration in Fermanagh yesterday, he called for a "peaceful Rising" in Ireland.