If this is possible, then isn't there going to be a chance to have a YY child?
I don't think it is possible. There is a lot happening to the DNA of the sperm and the egg after fertilization, and just mixing the DNA of two sperm or two eggs would not achieve that. Also, a YY embryo would not be viable because the X chromosome contain vital genes that Y does not. That's why there are people with 1X but no one with 1Y.
Well, it would be difficult from specifically sperm, but if you mean from two members of the same sex -- two men, then the answer is yes. Yes it is (or, rather, will be) possible. Already, it has been done in mice (new baby mice were born from both only mothers and also only fathers):
In theory it would never be possible for two women to truly fully independently create a son (a male offspring) from their own cells, because neither of them would have the material for a Y chromosome. So that would need to be donated (just the Y chromosome). Two males could make either sex offspring (XX or XY). This would be possible through what is called induced pluripotent stem cell technology, likely CRISPR genome editing for performing the required epigenetic modifications (described in paper), and a whole variety of other quite new extremely complex advances in biotechnology which have recently been made (such as next generation sequencing for assaying the most viable possible artificially-induced sperm and egg [which could simply be made from skin cells] and variations thereof like ATAC-seq, which measures genome-wide chromatin and epigenetic information, microfluidics and nano-droplet technologies and the rise of single-cell assay capabilities of many kinds, and truly, an overwhelming further number of huge advances which would take too long to list here and which most people probably remain totally unaware of [or could even comprehend, unfortunately]). We are living in a "Golden Age" of what will without a doubt be forever historic massive, rapid leaps forward in our ability to become the designers of life, rather than the passive victims of its "natural selection".
It is not possible today, all of the mice made in the 2018 study, though they did survive through to birth and then some, were quite unhealthy and all died prematurely from genetic abnormalities (does this not happen naturally, all the time, too? Not just in mice but men as well!). But there's no doubt the understanding and refinement of the ability to do such a thing will only rapidly improve - in every field of science this has been proven to be true in modern times, literally exponentially so. And probably no more amazing than in the scientific understanding and bioengineering of living things -- once the structure of DNA was chemically precisely determined and understood (in 1953; when it was revealed not only how DNA is chemically bonded and of precisely what atoms in what 3D orientations but also why such a structure, that specific double helix anti-parallel complementary form, would make sense functionally as a source of information-containing incredible power -- the relation of its structure to the function of evolution, and of literally the birth and aging process of every animal) is when things really started to proceed at a rocket-launch speed clip. Now, at this point, your average person really does not fathom just how much our world is about to change.
It's likely in this century this will be a safe, totally feasible, possible technological power at our disposal. Now will it be legal? That's much more uncertain. But that's irrelevant to the question of is it physically possible, to which the answer is an absolute yes.
No it is not possible,
sperm are missing most of the biochemical machinery need to produce a embryo, sperm have most most of their functional components to make them lower investment and faster. Sperm are lacking several important organelles, including the most important ribosomes. They are not fully functional cells.