Seventeen-year-old reality star Kylie Jenner is in a relationship with 25-year-old rapper, and father of one, Tyga. 

Tyga recently declared his feelings for Jenner on his Instagram page, sharing a picture of her with the caption: “Certain things catch your eye, but only few capture the heart.”

The pic caused mixed reactions on the social media site, with one commenter writing, “Good vocab. Now go back and Google statutory rape,” while another defended the couple saying, “Tyga and Kylie are only six years (apart) but age doesn’t matter. It only matters if you truly love them.”

(This defender is apparently not so great at math.)

Of course Jenner is not the first young woman to date an older musician. Pop star Hilary Duff was only 16 years old when she was in a serious relationship with rocker Benji Madden, 26. Even the King of Rock and Roll himself, Elvis Presley, dated 14-year-old Priscilla Presley when he was 24. He eventually married her when she turned 21.

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But Dr. Chloe Carmichael, a clinical psychologist who specializes in relationship issues, tells FOX411 that when it comes to these unions,“the relationship is not normal.”

“Tyga is actually 50 percent older than Kylie, which makes a big difference in terms of development at the age of 17. Kylie is so young that her cerebral cortex is still forming- the cerebral cortex is what helps us to strategize, consider future consequences, and put emotions into context," Carmichael said. "It's unhealthy because Kylie is in a 'one down position' by dating a man whose brain and body are fully formed while she is literally still developing.”

Carmichael says one issue may be that while Jenner is still in her teens, she has been exposed to a very mature world.

“She has grown up in a very adult world: nightclubs, tabloids, and observing seemingly endless relationship drama," she said. "It would probably be difficult for her to find someone her own age that could feel like a strong, manly romantic lead given her very adult-like teen experience so far.”

The youngest Jenner is definitely not your average teen. She’s a part of the biggest reality television dynasty, ‘Keeping Up with the Kardashians,” and has amassed worldwide fame. But entertainment journalist David Caplan says that with celebrity comes responsibility to her young fans.

“While Kylie may be mentally prepared to deal with such a relationship, the girls of that age who look up to her and who aspire to be her, are likely not," Caplan said. "That concerns me, as it does I'm sure the parents of Kylie's fans."

One parent who does not appear to be concerned, at least publicly, is momager Kris Jenner, who has yet to comment on the unlikely pair.

“As a parent Kris Jenner has a duty and obligation to make sure her daughter isn't growing up too fast," pop culture expert Valerie Greenberg said. "Judging by the way Kylie has been portraying herself as a sex object for the past couple years, at this age it's unacceptable ,and Kris should step in."

Caplan agrees that if Jenner wants to at least keep up appearances as a concerned mother she has to address her minor daughter’s relationship.

“Dating an underage girl is serious. This isn't some silly, light-hearted issue that Kris is being pressured into answering," Caplan said. "It needs to be taken seriously, and Kris should articulate the status of the relationship, and, as a mother what her input has been.”

Carmichael however contends Jenner has the right to privately handle the issue with her child. 

“It's hard to judge Kris Jenner for not giving a statement to the press," Carmichael said. "She may be giving very strong statements to Kylie at home, but simply choosing to avoid using the press as a way to communicate with her daughter."

WATCH: Hilary Duff's bikini REVENGE

 

Fox News.com Reporter and FOX411 host Diana Falzone covers celebrity news and interviews some of today's top celebrities and newsmakers.  You can follow her on Twitter @dianafalzone.