What are your thoughts on a protein called sgk1 being linked with infertity and miscarriages?

To early to say. A group of researchers published a study on oct 16 in the journal nature medicine showing a connection between high levels of sgk1 and infertility, and low levels and miscarriage. Apart from this observation, their conclusions were based on work with mice and cells, not with people. It may be a promising new avenue for infertility research, but it is probably too early for practical applications.
Too early to tell! The study you are talking about is brand-new and has not been repeated independently. Its sample size was small. More importantly, it is unknown if sgk1 levels in endometrium are affected by something else. The study never said sgk1 itself was mutated or defective in women with infertility or repeated miscarriage. Change in sgk1 levels may be a byproduct of some other cause. Need more research!
Link is unclear. One recent scientific paper showed mutations in a protein called sgk1 occurred more often in mice with infertility and pregnancy complications. However, since the study was done in mice, there is no strong evidence that a malfunctioning sgk1 gene or protein in humans would cause infertility. More importantly, a single research study in medicine can start ideas but rarely, if ever, gives an answer.