Custom Percentages...
MC Command Center > MC Occult > MC Occult > Other Pregnancy... > Custom Percentages...
Choose the Parent types to configure offspring percentages
Vampire and Human
Select the type of offspring below to specify the percentage for that offspring to be used in the current pregnancy rather than the EA defaults. Note that if zero is entered for all offspring types, then only human babies will be born.
Vampire and Alien
Select the type of offspring below to specify the percentage for that offspring to be used in the current pregnancy rather than the EA defaults. Note that if zero is entered for all offspring types, then only human babies will be born.