On Junia we had a thread about five years ago here.
A footnote in the NET at Rom 16:7 comments:
sn The feminine name Junia, though common in Latin, is quite rare in Greek (apparently only three instances of it occur in Greek literature outside Rom 16:7, according to the data in the TLG [D. Moo, Romans [NICNT], 922]). The masculine Junias (as a contraction for Junianas), however, is rarer still: Only one instance of the masculine name is known in extant Greek literature (Epiphanius mentions Junias in his Index discipulorum 125). Further, since there are apparently other husband-wife teams mentioned in this salutation (Prisca and Aquila [Rom 16:3], Philologus and Julia [Rom 16:15]), it might be natural to think of Junia as a feminine name. (This ought not be pressed too far, however, for in Rom 16:12 all three individuals are women [though the first two are linked together], and in Rom 16:9-11 all the individuals are men.) In Greek only a difference of accent distinguishes between Junias (male) and Junia (female). If it refers to a woman, it is possible (1) that she had the gift of apostleship (not the office), or (2) that she was not an apostle but along with Andronicus was esteemed by (or among) the apostles. As well, the term “prominent” probably means “well known,” suggesting that Andronicus and Junia(s) were well known to the apostles (see note on the phrase “well known” which follows).
Wikipedia also has an interesting article on the textual issues involved (here). As that article shows, it is also possible to render the verse in such a way that neither Andronicus nor Junia were apostles, but merely a well known couple to the apostles.
For the sake of the linked thread on Junia I am linking this post to it.