I personally disagree that these issues surrounding pregnancy constitutes discrimination, as it is a matter complicated by many aspects, including (among others) the reality that the mother must carry the child, the gestation time being quite short in legal terms, and different moral and religious positions regarding abortion. But, as b_b commented below, the father's rights do not effectively end at conception. There are legal options regarding disputes of custody, and judicial discretion allows for consideration of individual circumstances. No doubt, some judges will undervalue the father's position, but in every aspect of law there are unfair outcomes. I don't see this area as particularly skewed, although it is one fraught with bias and divergent morals.
As for the selective service, I feel that it should either be phased out, or include woman as well. However, it did start in 1917, and was created by an all-male congress, so this could be seen as a self-imposed discrimination.
In fact, in both cases, IMO the current structures exist in large part due to a long-standing view of maleness that includes "manning up" and taking care of the baby, or defending one's country. I wouldn't consider these to be modern views, but those inherited from a time when to 'be a man' meant something that was defined largely by men, apart from ideas of sexual equality. We can change these laws to make them more fair, but I don't see their origins as anti-male, but rather in an out-dated view of maleness in large part defined by males of yesteryear.