The probabilities of sets of twins are as follows.

Both Male: 1/4(1+theta)
Both Female: 1/4(1+theta)
Mixed Sex: 1/2(1-theta)

From a study of 200 pairs if twins:

Both Male= 78
Both Female= 59
Mixed= 63

Find the Likelihood and Maximum Likelikodd estimator for the data.

I've never dealt find findng likelihoods of datas, just of functions.
Can anyone help?!