How to automatically assign child taxonomy terms? I'm building a virtual network like Instagram but its contents (images) are about a certain event.  The strategy of selecting taxonomy terms is to display all of the tags (about 20 ones) and a checkbox and users can check any one of them. I use ttr_configurable_widget to do so.

The problem is there are many synonyms for a word and I don't want to display the synonyms, as an example in tagging the words female, women, girl, sister, daughter, lady are almost the same so when some one search for female the lady tag should be searched as well, furthermore this tag should be displayed as a hidden element in the web page(for search engines)

So there is a main tag like women and a set of synonyms. What I need to do is to format the tags as follow



Then only display the woman, when a user selects woman its synonyms also be attached to the content.

It is also preferred to load the synonyms but hide them in the node display page.

How can I do this?

The Taxonomy Term Reference Tree Widget and Taxonomy Group Fields are almost doing this but in these widgets users can check or uncheck the children even if the parent is selected.
The best way to achieve this job is using JQUERY,load all terms in the page  ,hide all of  children  terms and when the parent term checked show the children terms of it( also when unchecked hide all children of it).