The study scientists have an immature understanding of what is and is not possible with our DNA, given how our RNA does the transcribing of the genetic code and what can take place in that process.
A child can inherit a gene not present in either parent through de novo mutations, which are new genetic changes that occur spontaneously during the formation of sperm or egg cells or very early in embryonic development.
But I am sure the “ancient aliens” crowd will prefer the theory of alien origins of our DNA (as opposed to the science of naturally occurring gene mutation).
A Cosmic Ray, which is in reality just a super high speed particle travelling through space, would have to hit the sperm or ovum cell exactly right to change the DNA structure of the embryo that is growing. The odds are ‘astronomical’!...😎