Danutė is also used as a masculine name in Lithuanian, alongside Danielius. However, Danutė is more common for females. So, I think that the "Gender" of this name should be changed from "Feminine" to "Feminine & Masculine".Sources: https://www.names.org/n/danute/about https://forebears.io/x/forenames/danute
At the time of writing this comment, the description for this name states that its meaning is uncertain and that it could possibly be a Lithuanian feminine form of Daniel or a Lithuanian variant of Donata. Well, I was able to find more information about the name and I can tell you the following:1. The name Danutė is a diminutive, as it contains the well-documented Lithuanian feminine diminutive suffix -utė. When it comes to this, you might want to compare this with the Lithuanian name Laimutė in the main database, which is already correctly listed as a diminutive.2. Lithuanian sources all state that Danutė comes from Danielė, which is the Lithuanian feminine form of Daniel. Some of those sources state that it derives from Danielė via its short form Dana, but that doesn't really matter, as Danutė can easily be a diminutive of both Danielė and Dana. In fact, it can basically be the diminutive of any feminine given name that starts with Dan-.3. The Lithuanian form of Donata is Donatė, but it is extremely rare in Lithuania compared to Donata itself. That said, a diminutive that contains the suffix -utė would be Donutė for both names. The Lithuanian language contains numerous diminutive suffixes, but that is the only diminutive that you would get with the suffix -utė. So, all in all, Danutė cannot be a Lithuanian variant or diminutive of Donata and Donatė. However, Danutė and Donutė look eerily similar, so it isn't inconceivable that people have mistaken one for the other during the centuries, such as when reading old documents in old and barely legible handwriting.Alright, I believe that was all! Now the only thing left for me to do is to give you a list of the sources that I used:- https://de.wikipedia.org/wiki/Danut%C4%97 (in German) - https://www.tevu-darzelis.lt/vaiku-vardai/Danute/ (in Lithuanian; mentions that the name is a diminutive of Dana, which is a short form of Danielė) - http://www.vardai.org/vardo-reiksme/Danute/ (in Lithuanian; mentions that the name comes from Danielė) - http://day.lt/vardai/Danute (in Lithuanian; mentions that the name comes from Danielė) - http://vardai.vlkk.lt/vardas/Danute (in Lithuanian; mentions that the name contains a suffix) - http://www.thelithuanians.com/names/name2b.html (in English; mentions that the name contains the diminutive suffix -utė and ultimately comes from Danielė) - https://en.wikipedia.org/wiki/List_of_diminutives_by_language#Lithuanian (in English; lists some of the most common Lithuanian diminutive suffixes) - http://www.su.lt/index.php?option=com_content&view=article&id=3885:hf-fl-sn-2007-12&catid=459&Itemid=1264&lang=en (in English; scroll down to "The tendencies of addressing children in the family" written by Giedrė Čepaitienė)
Since "ute" is a common diminutive suffix used in many Lithuanian names (Laima, Laimute, Vaiva, Vaivute, etc, ) the name Danute might seem to come from "little Dana" in the same way Anita originates from "little Ana" in Spanish. This would not really hold true for the name Birute, since there is no such name as Bira, in Lithuanian. Both Danute and Birute were ancient patron goddesses associated for the vestal virgins who watched over a "sacred flame" kept burning in the center of each village in Old Europe.
Sources: https://www.names.org/n/danute/about
https://forebears.io/x/forenames/danute