The former Wimbledon champion was responding to commentators who have made the link between his on-court form since January and the birth of daughter Sophia in February.
Murray was knocked out of the Miami Open last month, losing a third-set lead.
Wife Kim told him she had read an article which “sort of blamed” the birth of their daughter for him losing a match, Murray told the Mail on Sunday newspaper.
“That’s actually a horrible thing to say. That’s not the case but so what if she did? Why does that matter?” he said.
“Becoming a parent is life-changing and if it helps my tennis, great. If it doesn’t, fine.”