Similar to this question with some very key differences.
In this human civilisation sex 1 (s1, represented by 'X') is a dominant allele and sex 2 (s2, represented by 'x') is recessive. There are obvious visual differences in these sexes.
There is a catch: in this world people of s2 sex may breed with other s2 sexed people with a normal mortality rate. People who are s1 (carriers of s2 or not) may breed with other s1 sexed people, however in this case there is a mortality rate of 50%.
Now using a 2x2 Punnett square the statistics are:
An s1 human that isn't a carrier of s2 (XX) breeding with an s2 (xx) results in each child being an s1 and a carrier of s2 (Xx)
Similarly, an s1 human that is a carrier of s2 (Xx) breeding with an s2 (xx) results in 50% s1 carrier of s2 (Xx) and 50% s2 (xx).
A pure s1 (XX) breeding with an s1 carrier (Xx) results in 25% pure s1 (XX), 25% carrier s1 (Xx) and 50% stillborn.
Two s1 carriers (Xx) breeding results in 12.5% pure s1 (XX), 12.5% s2 (xx), 25% s1 carrier (Xx), 50% stillborn.
Two s2s (xx) breeding results in 100% s2 (xx)
Two pure s1s (XX) results in 50% pure s1 (XX), 50% stillbirths.
What would be the resultant civilisation in gender roles, societal structure etc?
Forgive me if I have broken any unspoken rules of stackexchange; I'm relatively new.