Board Thread:Questions and Answers/@comment-1631127-20160703153301

They have too much similarities example:

1) Heart Egg (Kokoro no Tamago) are similar to Heart Flower (Kokoro no Hana) both can be corrupted.  has a similar meaning Heart Egg also know as Guardian Eggs of them you can be born a little fairy fairy that represents the personality and dreams of the owner. A small difference Heart Egg they disappear to grow except for some cases

2) Transformation Phrase's similar in Shugo Chara  "Watashi Kokoro Unlock" while in Heartcatch is "Precure, Open My Heart"

3) In Shugo Chara a male protagonist crossdressing as girl, while in hearthcatch is female protagonist crossdressing as boy both by familiar reason

4) Both series use a garden as headquarters in Shugo Chara is Seiyo Academy Royal Garden while Heartcatch is Hanasaki Botanical Garden.

There are several differences also events in "Shugo Chara" are during Elementary School,  other main character is only one that can purify the "X Eggs or X-Chara"

A crossover between these two series could be great. As another exception to see the "Guardian Character" is to have a pure heart.  