(CNN) Just months after Republican Kevin Nicholson announced his bid to unseat incumbent Democratic Sen. Tammy Baldwin in 2018, his own parents donated the legal maximum to her primary campaign.

Nicholson announced last July that he would seek the Republican nomination for US Senate in Wisconsin. A Federal Election Commission filing by Baldwin's campaign dated February 5 and available online shows that each of Nicholson's parents, Donna and Michael, donated $2,700 to Baldwin in December 2017. FEC rules stipulate that those donations are the maximum Nicholson's parents can donate to Baldwin during the primary election. They can donate up to that amount again during the general election.

Their donations are not necessarily out of character: Nicholson has said on the campaign trail that he comes from a Democratic family and, as the Milwaukee Journal-Sentinel reported in November, his mother has donated thousands of dollars over the years to Democratic organizations and candidates, including hundreds to Baldwin.

However, the contributions are the first his parents have given to Baldwin since Nicholson announced his candidacy to try to oust the senator.

In a statement to CNN, Nicholson said, "My parents have a different worldview than I do, and it is not surprising that they would support a candidate like Tammy Baldwin who shares their perspective."

He continued, "I'm a conservative today not because I was born one, but because of the experience I earned as a Marine in combat, my experience as a husband and father, my choice to be a Christian, the schools I chose to attend and the decision to pursue the career that I have. Regardless of who may disagree with my life decisions, I would not trade these experiences for anything, and they will always guide my views as Wisconsin's next U.S. Senator."

Donna and Michael Nicholson did not return requests for comment.

Nicholson has previously faced questions about his political views as a younger man, when he was president of the College Democrats of America and spoke at the 2000 Democratic National Convention. Nicholson told Politico for a September story that his opinions permanently changed after his 2007 deployment to Iraq, when he became "livid" with Democrats' opposition to the war.

"I knew what we were doing there," he said. "We were stabilizing that country. We made incredible amounts of progress. And what I was hearing back home was a complete and absolute lie, as politicians were running around calling it a failure."

After Nicholson was caught on tape criticizing fellow Republican Wisconsinite and House Speaker Paul Ryan, Nicholson campaign spokesman Michael Antonopoulos strongly rejected the notion that the candidate shared his mother's views, as she has donated to a political action committee supporting Ryan's Democratic challenger.

"This is an absurd and disingenuous question," Antonopoulos told the Milwaukee Journal-Sentinel in November. "Kevin is a conservative who supports Speaker Ryan and has stated repeatedly that he comes from a family of Democrats."